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Mentré O, Leclercq B, Arevalo-Lopez AM, Pautrat A, Petit S, Minaud C, Daviero-Minaud S, Hovhannisyan RA, Stolyarov VS. Multivalued Memory via Freezing of Super-Hard Magnetic Domains in a Quasi 2D-Magnet. Small Methods 2023; 7:e2300491. [PMID: 37490517 DOI: 10.1002/smtd.202300491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 06/26/2023] [Indexed: 07/27/2023]
Abstract
The design of high-density non-volatile memories is a long-standing dream, limited by conventional storage "0" or "1" bits. An alternative paradigm exists in which regions within candidate materials can be magnetized to intermediate values between the saturation limits. In principle, this paves the way to multivalued bits, vastly increasing storage density. Single-molecule magnets, are good examples offering transitions between intramolecular quantum levels, but require ultra-low temperatures and limited relaxation time between magnetization states. It is showed here that the quasi 2D-Ising compound BaFe2 (PO4 )2 overcomes these limitations. The combination of giant magneto-crystalline anisotropy, strong ferromagnetic exchange, and strong intrinsic pinning creates remarkably narrow magnetic domain walls, collectively freezing under Tf ≈15 K. This results in a transition from a soft to a super-hard magnet (coercive force > 14 T). Any magnetization can then be printed and robustly protected from external fields with an energy barrier >9T at 2 K.
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Affiliation(s)
- Olivier Mentré
- UCCS - Axe Chimie du Solide - Groupe MISSP, UMR-CNRS 8181, Université de Lille, Cedex, 59652, France
| | - Bastien Leclercq
- UCCS - Axe Chimie du Solide - Groupe MISSP, UMR-CNRS 8181, Université de Lille, Cedex, 59652, France
| | - Angel M Arevalo-Lopez
- UCCS - Axe Chimie du Solide - Groupe MISSP, UMR-CNRS 8181, Université de Lille, Cedex, 59652, France
| | - Alain Pautrat
- CRISMAT, CNRS, Normandie Univ, ENSICAEN, UNICAEN, Caen, 14050, France
| | - Sylvain Petit
- Laboratoire Léon Brillouin, CEA, CNRS, Université Paris-Saclay, Gif sur Yvette Cedex, F-91191, France
| | - Claire Minaud
- Institut Michel-Eugène Chevreul - CNRS (FR2638), Université de Lille, Université d'Artois, Centrale Lille, CNRS, l'INRAE, Villeneuve-d'Ascq, 59650, France
| | - Sylvie Daviero-Minaud
- UCCS - Axe Chimie du Solide - Groupe MISSP, UMR-CNRS 8181, Université de Lille, Cedex, 59652, France
| | - Razmik A Hovhannisyan
- Advanced Mesoscience and Nanotechnology Centre, Moscow Institute of Physics and Technology, Dolgoprudny, 141700, Russia
| | - Vasily S Stolyarov
- Advanced Mesoscience and Nanotechnology Centre, Moscow Institute of Physics and Technology, Dolgoprudny, 141700, Russia
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2
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Podchezertsev S, Barrier N, Pautrat A, Suard E, Retuerto M, Alonso JA, Fernández-Díaz MT, Rodríguez-Carvajal J. Influence of Polymorphism on the Magnetic Properties of Co 5TeO 8 Spinel. Inorg Chem 2021; 60:13990-14001. [PMID: 34496217 DOI: 10.1021/acs.inorgchem.1c01131] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study presents the influence of polymorphism on the magnetic properties of Co5TeO8. This compound with a spinel-like structure [Co2]A[Co3Te]BO8 was synthesized into two polymorphs: one disordered within a cubic Fd3̅m structure, where Co2+ and Te6+ ions are randomly distributed on the octahedral B sites [the disordered polymorph can also be presented as an inverse spinel of the formula Co(Co1.5Te0.5)O4] and the other ordered with a cubic P4332 structure where Co2+ and Te6+ ions are ordered on the B sites. The macroscopic magnetic measurements showed that both polymorphs present a ferrimagnetic ordering, below ∼40 K, and a second transition is also observed at 27 K for the ordered polymorph. Neutron powder diffraction data between room temperature and 1.7 K showed as well the presence of short-range magnetic ordered clusters, which appears for both polymorphs below 200 K. At lower temperature, these short-range orders are transformed into long-range ferrimagnetic orders. Below TC = 40 K, the colinear ferrimagnetic structure of the disordered polymorph is described with the I41/am'd' space group. The ordered polymorph undergoes an incommensurate ferrimagnetic spiral spin ordering below TC1 = 45 K, followed by a second magnetic phase transition at TC2 = 27 K. This last transition is associated with the emergence of an additional ferrimagnetic component and an abrupt change in the magnitude of the magnetic propagation vector k = [0, 0, γ] from γ = 0.086 at T = 30 K to γ ≈ 0.14 in the range between 27 and 1.7 K. The magnetic symmetry of the ordered polymorph is described with the P43(00γ)0 magnetic superspace group. We evidenced that the ordering of Co2+/Te6+ on the B sites changes all of the Co-Co and Co-O distances and thus all JAB, JAA, and JBB exchange interactions, between the A and B sites, which are able to stabilize the incommensurate spin modulation in the ordered polymorph.
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Affiliation(s)
- Stanislav Podchezertsev
- Normandie Université, ENSICAEN, UNICAEN, CNRS, CRISMAT, Caen 14000, France.,Institut Laue Langevin (ILL), Grenoble 9 F-38042, France
| | - Nicolas Barrier
- Normandie Université, ENSICAEN, UNICAEN, CNRS, CRISMAT, Caen 14000, France
| | - Alain Pautrat
- Normandie Université, ENSICAEN, UNICAEN, CNRS, CRISMAT, Caen 14000, France
| | | | - María Retuerto
- Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, Madrid E-28049, Spain
| | - Jose Antonio Alonso
- Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, Madrid E-28049, Spain
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3
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Minelli A, Duverger-Nedellec E, Pautrat A, Pérez O, Mihalkovic M, De Boissieu M, Bosak A, Goodwin A. The interplay of framework instability and electron–phonon coupling in a CDW system, the monophosphate tungsten bronze family. Acta Crystallogr A Found Adv 2021. [DOI: 10.1107/s0108767321092862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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4
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Kumar D, David A, Fouchet A, Pautrat A, Boullay P, Jung CU, Prellier W. Strong Magnetic Anisotropy of Epitaxial PrVO 3 Thin Films on SrTiO 3 Substrates with Different Orientations. ACS Appl Mater Interfaces 2020; 12:35606-35613. [PMID: 32805796 DOI: 10.1021/acsami.0c07794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We have probed the structural and magnetic properties of PrVO3 (PVO) thin films grown on the (001)-, (110)-, and (111)-oriented SrTiO3 (STO) substrates. By changing the substrate orientation, the film out-of-plane orientation can be tuned to [110], [100]/[010], and [011]/[311], with different in-plane crystallographic variants. Accommodation of these variants on the different substrates implies different strain states, which have direct influence on the magnetic properties of PVO films. The magnetic moment of PVO films radically enhances from 0.4 μB/f.u. for STO(001) to 2.3 μB/f.u. for STO(111). While films on the (001)-oriented STO substrate display out-of-plane anisotropy, an in-plane anisotropy is observed for films grown on the (110)- and (111)-oriented STO substrates. In addition, a strong uniaxial magnetic anisotropy is also extracted for a partially relaxed film on the (110)-oriented STO substrate. Such findings can help oxide community for the better understanding of magnetic anisotropy in vanadate thin films, a subject that still suffer from significant lack of scientific investigations.
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Affiliation(s)
- Deepak Kumar
- Normandie Université, UNICAEN, ENSICAEN, Laboratoire CRISMAT, CNRS UMR 6508, Caen Cedex 4 F-14050, France
| | - Adrian David
- Normandie Université, UNICAEN, ENSICAEN, Laboratoire CRISMAT, CNRS UMR 6508, Caen Cedex 4 F-14050, France
| | - Arnaud Fouchet
- Normandie Université, UNICAEN, ENSICAEN, Laboratoire CRISMAT, CNRS UMR 6508, Caen Cedex 4 F-14050, France
| | - Alain Pautrat
- Normandie Université, UNICAEN, ENSICAEN, Laboratoire CRISMAT, CNRS UMR 6508, Caen Cedex 4 F-14050, France
| | - Philippe Boullay
- Normandie Université, UNICAEN, ENSICAEN, Laboratoire CRISMAT, CNRS UMR 6508, Caen Cedex 4 F-14050, France
| | - Chang Uk Jung
- Department of Physics, Oxide Research Center, Hankuk University of Foreign Studies, Yongin, Gyeonggi 17035, Korea
| | - Wilfrid Prellier
- Normandie Université, UNICAEN, ENSICAEN, Laboratoire CRISMAT, CNRS UMR 6508, Caen Cedex 4 F-14050, France
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Duverger-Nédellec E, Pautrat A, Kolincio KK, Hervé L, Pérez O. Cascading transitions toward unconventional charge density wave states in the quasi-two-dimensional monophosphate tungsten bronze P 4W 16O 56. IUCrJ 2020; 7:184-192. [PMID: 32148847 PMCID: PMC7055383 DOI: 10.1107/s2052252519016695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 12/12/2019] [Indexed: 06/10/2023]
Abstract
Single crystals of the m = 8 member of the low-dimensional monophosphate tungsten bronzes (PO2)4(WO3)2m family were grown by chemical vapour transport technique and the high crystalline quality obtained allowed a reinvestigation of the physical and structural properties. Resistivity measurements revealed three anomalies at T C1 = 258 K, T C2 = 245 K and T C3 = 140 K, never observed until now. Parallel X-ray diffraction investigations showed a specific signature associated with three structural transitions, i.e. the appearance of different sets of satellite reflections below T C1, T C2 and T C3. Several harmonics of intense satellite reflections were observed, reflecting the non-sinusoidal nature of the structural modulations and a strong electron-phonon coupling in the material. These transitions could be associated with the formation of three successive unconventional charge density wave states.
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Affiliation(s)
- Elen Duverger-Nédellec
- CRISMAT, ENSICAEN/CNRS UMR6508, 6 Boulevard du Maréchal Juin, Caen, Normandie 14050, France
| | - Alain Pautrat
- CRISMAT, ENSICAEN/CNRS UMR6508, 6 Boulevard du Maréchal Juin, Caen, Normandie 14050, France
| | - Kamil K. Kolincio
- Faculty of Applied Physics and Mathematics, Gdansk University of Technology, Narutowicza 11/12, Gdansk 80-233, Poland
| | - Laurence Hervé
- CRISMAT, ENSICAEN/CNRS UMR6508, 6 Boulevard du Maréchal Juin, Caen, Normandie 14050, France
| | - Olivier Pérez
- CRISMAT, ENSICAEN/CNRS UMR6508, 6 Boulevard du Maréchal Juin, Caen, Normandie 14050, France
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6
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7
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Boileau A, Dallocchio M, Baudouin F, David A, Lüders U, Mercey B, Pautrat A, Demange V, Guilloux-Viry M, Prellier W, Fouchet A. Textured Manganite Films Anywhere. ACS Appl Mater Interfaces 2019; 11:37302-37312. [PMID: 31512470 DOI: 10.1021/acsami.9b12209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
New paradigms are required in microelectronics when the transistor is in its downscaling limit and integration of materials presenting functional properties not available in classical silicon is one of the promising alternatives. Here, we demonstrate the possibility to grow La0.67Sr0.33MnO3 (LSMO) functional materials on amorphous substrates with properties close to films grown on single-crystalline substrates using a two-dimensional seed layer. X-ray diffraction and electron backscatter diffraction mapping demonstrate that the Ca2Nb3O10- nanosheet (NS) layer induces epitaxial stabilization of LSMO films with a strong out-of-plane (001) texture, whereas the growth of LSMO films on uncoated glass substrates exhibits a nontextured polycrystalline phase. The magnetic properties of LSMO films deposited on NS are similar to those of the LSMO grown on SrTiO3 single-crystal substrates in the same conditions (which is used as a reference in this work). Moreover, transport measurements take advantages of the texture and polycrystalline properties to induce low-field magnetoresistance at low temperature and also a high value of 40% magnetoresistance from 10 to 300 K, making it interesting for sensor applications. Therefore, the NS seed layer offers new perspectives for the integration of functional materials grown at moderate temperatures on any substrate, which will be the key for the development of oxitronics.
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Affiliation(s)
- Alexis Boileau
- Normandie Univ, ENSICAEN, UNICAEN, CNRS, CRISMAT , 14000 Caen , France
| | - Marie Dallocchio
- Normandie Univ, ENSICAEN, UNICAEN, CNRS, CRISMAT , 14000 Caen , France
| | - Florent Baudouin
- ISCR Univ Rennes, CNRS, ISCR-UMR 6226, ScanMAT-UMS 2001 , F-35000 Rennes , France
| | - Adrian David
- Normandie Univ, ENSICAEN, UNICAEN, CNRS, CRISMAT , 14000 Caen , France
| | - Ulrike Lüders
- Normandie Univ, ENSICAEN, UNICAEN, CNRS, CRISMAT , 14000 Caen , France
| | - Bernard Mercey
- Normandie Univ, ENSICAEN, UNICAEN, CNRS, CRISMAT , 14000 Caen , France
| | - Alain Pautrat
- Normandie Univ, ENSICAEN, UNICAEN, CNRS, CRISMAT , 14000 Caen , France
| | - Valérie Demange
- ISCR Univ Rennes, CNRS, ISCR-UMR 6226, ScanMAT-UMS 2001 , F-35000 Rennes , France
| | | | - Wilfrid Prellier
- Normandie Univ, ENSICAEN, UNICAEN, CNRS, CRISMAT , 14000 Caen , France
| | - Arnaud Fouchet
- Normandie Univ, ENSICAEN, UNICAEN, CNRS, CRISMAT , 14000 Caen , France
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8
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Leclercq B, Kabbour H, Damay F, Colin CV, Pautrat A, Arevalo-Lopez AM, Mentré O. Metamagnetic Transitions versus Magnetocrystalline Anisotropy in Two Cobalt Arsenates with 1D Co2+ Chains. Inorg Chem 2019; 58:12609-12617. [DOI: 10.1021/acs.inorgchem.9b01303] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bastien Leclercq
- UCCS, UMR-CNRS 8181, Université Lille-ENSCL, Avenue Mendeleiev, 59655 Villeneuve d’Ascq, France
| | - Houria Kabbour
- UCCS, UMR-CNRS 8181, Université Lille-ENSCL, Avenue Mendeleiev, 59655 Villeneuve d’Ascq, France
| | - Françoise Damay
- Laboratoire Léon Brillouin, UMR12-CNRS, CEA Saclay, Bât. 563, 91191 Gif-Sur-Yvette, France
| | - Claire V. Colin
- Institut NEEL, CNRS/UGA UPR2940, CNRS/UGA UPR2940, 25 rue des Martyrs, 38042 Grenoble, France
| | - Alain Pautrat
- Laboratoire CRISTMAT, UMR 6508-CNRS, ENSICAEN, 6 Bd. Du Maréchal Juin, 14000 Caen, France
| | - Angel M. Arevalo-Lopez
- UCCS, UMR-CNRS 8181, Université Lille-ENSCL, Avenue Mendeleiev, 59655 Villeneuve d’Ascq, France
| | - Olivier Mentré
- UCCS, UMR-CNRS 8181, Université Lille-ENSCL, Avenue Mendeleiev, 59655 Villeneuve d’Ascq, France
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9
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Duverger-Nédellec E, Kolincio K, Hervé L, Pautrat A, Pérez O. Evidencing of charge density wave instabilities in even members of the monophosphate tungsten bronzes family. Acta Crystallogr A Found Adv 2019. [DOI: 10.1107/s2053273319091812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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10
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Steciuk G, David A, Petříček V, Palatinus L, Mercey B, Prellier W, Pautrat A, Boullay P. Precession electron diffraction tomography on twinned crystals: application to CaTiO 3 thin films. J Appl Crystallogr 2019. [DOI: 10.1107/s1600576719005569] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
Strain engineering via epitaxial thin-film synthesis is an efficient way to modify the crystal structure of a material in order to induce new features or improve existing properties. One of the challenges in this approach is to quantify structural changes occurring in these films. While X-ray diffraction is the most widely used technique for obtaining accurate structural information from bulk materials, severe limitations appear in the case of epitaxial thin films. This past decade, precession electron diffraction tomography has emerged as a relevant technique for the structural characterization of nano-sized materials. While its usefulness has already been demonstrated for solving the unknown structure of materials deposited in the form of thin films, the frequent existence of orientation variants within the film introduces a severe bias in the structure refinement, even when using the dynamical diffraction theory to calculate diffracted intensities. This is illustrated here using CaTiO3 films deposited on SrTiO3 substrates as a case study. By taking into account twinning in the structural analysis, it is shown that the structure of the CaTiO3 films can be refined with an accuracy comparable to that obtained by dynamical refinement from non-twinned data. The introduction of the possibility to handle twin data sets is undoubtedly a valuable add-on and, notably, paves the way for a successful use of precession electron diffraction tomography for accurate structural analyses of thin films.
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Poupon M, Barrier N, Pautrat A, Petit S, Perez O, Bazin P. Investigation of Co6(OH)3(TeO3)4(OH)~0.9(H20): Synthesis, crystal and magnetic structures, magnetic and dielectric properties. J SOLID STATE CHEM 2019. [DOI: 10.1016/j.jssc.2018.11.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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12
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Duverger-Nédellec E, Pautrat A, Pérez O. Transitions towards complex electronic states and superperiodic structures in P 4W 16O 56. Acta Crystallogr A Found Adv 2018. [DOI: 10.1107/s2053273318093816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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13
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Steciuk G, Barrier N, Pautrat A, Boullay P. Stairlike Aurivillius Phases in the Pseudobinary Bi 5Nb 3O 15-ABi 2Nb 2O 9 (A = Ba and Sr) System: A Comprehensive Analysis Using Superspace Group Formalism. Inorg Chem 2018; 57:3107-3115. [PMID: 29474066 DOI: 10.1021/acs.inorgchem.7b03026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report the possibility of extending the so-called stairlike Aurivilius phases in the pseudobinary Bi5Nb3O15-ABi2Nb2O9 (A = Ba and Sr) over a wide range of compositions. These phases are characterized by a discontinuous stacking of [Bi2O2] slabs and perovskite blocks, leading to long-period intergrowths stabilized as a single phase. When analyses from precession electron diffraction tomography and X-ray and neutron powder diffraction are combined, the monoclinic incommensurately modulated structure with q = αa* + γc* previously proposed for the ABi7Nb5O24 composition could be generalized to the Bi5Nb3O15-ABi2Nb2O9 (A = Ba and Sr) compounds. Considering the compositions expressed as (A,Bi)1- xNb xO3-3 x, the stacking sequence associated with compositions ranging from x = 2/5 to 3/8 is governed by the component γ of the modulation vector and can be predicted following a Farey tree hierarchy independently to the A cation. The length of the steps, characteristic of the stairlike nature, is controlled by the α component and depends on the substitution ratio A/Bi and the nature of A (A = Ba and Sr). This study highlights the compositional flexibility of stairlike Aurivillius phases.
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Affiliation(s)
- Gwladys Steciuk
- CRISMAT, Normandie Université, ENSICAEN, UNICAEN, CNRS UMR 6508 , 6 Bd Maréchal Juin , F-14050 Caen Cedex 4 , France.,Institute of Physics of the Czech Academy of Sciences , Na Slovance 2 , Prague , Czech Republic
| | - Nicolas Barrier
- CRISMAT, Normandie Université, ENSICAEN, UNICAEN, CNRS UMR 6508 , 6 Bd Maréchal Juin , F-14050 Caen Cedex 4 , France
| | - Alain Pautrat
- CRISMAT, Normandie Université, ENSICAEN, UNICAEN, CNRS UMR 6508 , 6 Bd Maréchal Juin , F-14050 Caen Cedex 4 , France
| | - Philippe Boullay
- CRISMAT, Normandie Université, ENSICAEN, UNICAEN, CNRS UMR 6508 , 6 Bd Maréchal Juin , F-14050 Caen Cedex 4 , France
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14
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Gonano B, Bréard Y, Pelloquin D, Caignaert V, Pérez O, Pautrat A, Bazin P, Suard E, Boullay P. Deciphering local complex order by HAADF in a disordered mixed polyanion iron oxide: Sr4Fe2[Fe0.5(SO4)0.25(CO3)0.25]O7.25. Dalton Trans 2018; 47:13088-13093. [DOI: 10.1039/c8dt02146e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Compound Sr4Fe2.5O7.25(SO4)0.25(CO3)0.25 shows a complex local order between polyanions which has been highlighted by means of neutron diffraction and HAADF.
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Affiliation(s)
- Bruno Gonano
- Laboratoire CRISMAT
- UMR 6508 CNRS ENSICAEN
- 14050 CAEN Cedex 4
- France
| | - Yohann Bréard
- Laboratoire CRISMAT
- UMR 6508 CNRS ENSICAEN
- 14050 CAEN Cedex 4
- France
| | - Denis Pelloquin
- Laboratoire CRISMAT
- UMR 6508 CNRS ENSICAEN
- 14050 CAEN Cedex 4
- France
| | | | - Olivier Pérez
- Laboratoire CRISMAT
- UMR 6508 CNRS ENSICAEN
- 14050 CAEN Cedex 4
- France
| | - Alain Pautrat
- Laboratoire CRISMAT
- UMR 6508 CNRS ENSICAEN
- 14050 CAEN Cedex 4
- France
| | - Philippe Bazin
- Laboratoire LCS
- UMR 6506 CNRS ENSICAEN
- 14050 CAEN Cedex 4
- France
| | | | - Philippe Boullay
- Laboratoire CRISMAT
- UMR 6508 CNRS ENSICAEN
- 14050 CAEN Cedex 4
- France
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15
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Gonano B, Bréard Y, Pelloquin D, Caignaert V, Perez O, Pautrat A, Boullay P, Bazin P, Le Breton JM. Combining Multiscale Approaches for the Structure Determination of an Iron Layered Oxysulfate: Sr 4Fe 2.5O 7.25(SO 4) 0.5. Inorg Chem 2017; 56:15241-15250. [PMID: 29215869 DOI: 10.1021/acs.inorgchem.7b02572] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The new iron layered oxysulfate Sr4Fe2.5O7.25(SO4)0.5 has been prepared by a solid-state reaction in closed ampules into the form of ceramics and single crystals. Its atomic structure has been solved by means of spectroscopy, diffraction techniques, and high-resolution electron microscopy. Sr4Fe2.5O7.25(SO4)0.5 is a layered structure that derives from the Ruddelsden-Popper (RP) phases with the layer stacking sequence SrO/SrFeO2.5/SrFe0.5(SO4)0.5O1.25/SrFeO2.5. Within the mixed Fe3+/SO42- layer, the sulfur atoms are slightly shifted from the B site of the perovskite and each sulfate group shares two corners with iron pyramids in the basal plan without any order phenomenon. The electronic conductivity is thermally activated, while no ionic conductivity is detected.
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Affiliation(s)
- Bruno Gonano
- Laboratoire CRISMAT, UMR 6508 CNRS ENSICAEN , 6 bd du Maréchal Juin, 14050 Caen Cedex 4, France
| | - Yohann Bréard
- Laboratoire CRISMAT, UMR 6508 CNRS ENSICAEN , 6 bd du Maréchal Juin, 14050 Caen Cedex 4, France
| | - Denis Pelloquin
- Laboratoire CRISMAT, UMR 6508 CNRS ENSICAEN , 6 bd du Maréchal Juin, 14050 Caen Cedex 4, France
| | - Vincent Caignaert
- Laboratoire CRISMAT, UMR 6508 CNRS ENSICAEN , 6 bd du Maréchal Juin, 14050 Caen Cedex 4, France
| | - Olivier Perez
- Laboratoire CRISMAT, UMR 6508 CNRS ENSICAEN , 6 bd du Maréchal Juin, 14050 Caen Cedex 4, France
| | - Alain Pautrat
- Laboratoire CRISMAT, UMR 6508 CNRS ENSICAEN , 6 bd du Maréchal Juin, 14050 Caen Cedex 4, France
| | - Philippe Boullay
- Laboratoire CRISMAT, UMR 6508 CNRS ENSICAEN , 6 bd du Maréchal Juin, 14050 Caen Cedex 4, France
| | - Philippe Bazin
- Laboratoire LCS, UMR 6506 CNRS ENSICAEN , 6 bd du Maréchal Juin, 14050 Caen Cedex 4, France
| | - Jean-Marie Le Breton
- Groupe de Physique des Matériaux, UMR 6634 CNRS-Université de Rouen , Site universitaire du Madrillet, avenue de l'Université - BP 12, 76801 Saint Etienne du Rouvray Cedex, France
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Pérez O, Duverger-Nédellec E, Pautrat A, Kolincio K. Transitions toward complex electronic states and superperiodic structures in MPTBp. Acta Crystallogr A Found Adv 2017. [DOI: 10.1107/s2053273317084546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Nicoud S, Huvé M, Hernandez O, Pautrat A, Duttine M, Wattiaux A, Colin C, Kabbour H, Mentré O. Comprehensive Study of Oxygen Storage in YbFe 2O 4+x (x ≤ 0.5): Unprecedented Coexistence of FeO n Polyhedra in One Single Phase. J Am Chem Soc 2017; 139:17031-17043. [PMID: 29094941 DOI: 10.1021/jacs.7b06409] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The multiferroic LuFe2.5+2O4 was recently proposed as a promising material for oxygen storage due to its easy reversible oxidation into LuFe3+2O4.5. We have investigated the similar scenario in YbFe2O4+x, leading to a slightly greater oxygen storage (OSC) capacity of 1434 μmol O/g. For the first time, the structural model of LnFe2O4.5 was fully understood by high-resolution microscopy images, and synchrotron and neutron diffraction experiments, as well as maximum entropy method. The oxygen uptake promotes a reconstructive shearing of the [YbO2] sub-units controlled by the adaptive Ln/Fe oxygen coordination and the Fe2/3+ redox. After oxidation, the rearrangement of the Fe coordination polyhedra is unique such that all available FeOn units (n = 6, 5, 4 in octahedra, square pyramids, trigonal bipyramids, tetrahedra) were identified in modulated rows growing in plane. This complex pseudo-ordering gives rise to short-range antiferromagnetic correlation within an insulating state.
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Affiliation(s)
- Sarah Nicoud
- Unité de Catalyse et Chimie du Solide (UCCS), CNRS - UMR 8181, Université d'Artois, ENSCL, Université de Lille , F-59000 Lille, France
| | - Marielle Huvé
- Unité de Catalyse et Chimie du Solide (UCCS), CNRS - UMR 8181, Université d'Artois, ENSCL, Université de Lille , F-59000 Lille, France
| | - Olivier Hernandez
- ISCR, CNRS - UMR 6226, Université de Rennes 1 , F-35042 Rennes, France
| | - Alain Pautrat
- CRISMAT, CNRS - UMR 6508, ENSICAEN , F-14050 Caen, France
| | - Mathieu Duttine
- ICMCB, CNRS - UPR 9048, Université Bordeaux , F-33600 Pessac, France
| | - Alain Wattiaux
- ICMCB, CNRS - UPR 9048, Université Bordeaux , F-33600 Pessac, France
| | - Claire Colin
- Institut NEEL, Université Grenoble Alpes , F-38000 Grenoble, France
| | - Houria Kabbour
- Unité de Catalyse et Chimie du Solide (UCCS), CNRS - UMR 8181, Université d'Artois, ENSCL, Université de Lille , F-59000 Lille, France
| | - Olivier Mentré
- Unité de Catalyse et Chimie du Solide (UCCS), CNRS - UMR 8181, Université d'Artois, ENSCL, Université de Lille , F-59000 Lille, France
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Copie O, Varignon J, Rotella H, Steciuk G, Boullay P, Pautrat A, David A, Mercey B, Ghosez P, Prellier W. Chemical Strain Engineering of Magnetism in Oxide Thin Films. Adv Mater 2017; 29:1604112. [PMID: 28370578 DOI: 10.1002/adma.201604112] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 02/20/2017] [Indexed: 06/07/2023]
Abstract
Transition metal oxides having a perovskite structure form a wide and technologically important class of compounds. In these systems, ferroelectric, ferromagnetic, ferroelastic, or even orbital and charge orderings can develop and eventually coexist. These orderings can be tuned by external electric, magnetic, or stress field, and the cross-couplings between them enable important multifunctional properties, such as piezoelectricity, magneto-electricity, or magneto-elasticity. Recently, it has been proposed that additional to typical fields, the chemical potential that controls the concentration of ion vacancies in these systems may reveal an efficient alternative parameter to further tune their properties and achieve new functionalities. In this study, concretizing this proposal, the authors show that the control of the content of oxygen vacancies in perovskite thin films can indeed be used to tune their magnetic properties. Growing PrVO3 thin films epitaxially on an SrTiO3 substrate, the authors reveal a concrete pathway to achieve this effect. The authors demonstrate that monitoring the concentration of oxygen vacancies through the oxygen partial pressure or the growth temperature can produce a substantial macroscopic tensile strain of a few percent. In turn, this strain affects the exchange interactions, producing a nontrivial evolution of Néel temperature in a range of 30 K.
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Affiliation(s)
- Olivier Copie
- Normandie Univ., ENSICAEN, UNICAEN, CNRS, CRISMAT, 6 Boulevard Maréchal Juin, F-14050, Caen, Cedex 4, France
- Institut Jean Lamour, UMR 7198 CNRS-Université de Lorraine, F-54506, Vandœuvre-lès-Nancy, France
| | - Julien Varignon
- Theoretical Materials Physics, Q-MAT, CESAM, Université de Liège, Allée du 6 août, 20, 4000, Sart Tilman, Belgium
- Unité Mixte de Physique UMR 137 CNRS/Thales, 1 avenue A. Fresnel, 91767, Palaiseau, France
- Université Paris-Sud, 91405, Orsay, France
| | - Hélène Rotella
- Normandie Univ., ENSICAEN, UNICAEN, CNRS, CRISMAT, 6 Boulevard Maréchal Juin, F-14050, Caen, Cedex 4, France
| | - Gwladys Steciuk
- Normandie Univ., ENSICAEN, UNICAEN, CNRS, CRISMAT, 6 Boulevard Maréchal Juin, F-14050, Caen, Cedex 4, France
| | - Philippe Boullay
- Normandie Univ., ENSICAEN, UNICAEN, CNRS, CRISMAT, 6 Boulevard Maréchal Juin, F-14050, Caen, Cedex 4, France
| | - Alain Pautrat
- Normandie Univ., ENSICAEN, UNICAEN, CNRS, CRISMAT, 6 Boulevard Maréchal Juin, F-14050, Caen, Cedex 4, France
| | - Adrian David
- Normandie Univ., ENSICAEN, UNICAEN, CNRS, CRISMAT, 6 Boulevard Maréchal Juin, F-14050, Caen, Cedex 4, France
| | - Bernard Mercey
- Normandie Univ., ENSICAEN, UNICAEN, CNRS, CRISMAT, 6 Boulevard Maréchal Juin, F-14050, Caen, Cedex 4, France
| | - Philippe Ghosez
- Theoretical Materials Physics, Q-MAT, CESAM, Université de Liège, Allée du 6 août, 20, 4000, Sart Tilman, Belgium
| | - Wilfrid Prellier
- Normandie Univ., ENSICAEN, UNICAEN, CNRS, CRISMAT, 6 Boulevard Maréchal Juin, F-14050, Caen, Cedex 4, France
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Dellicour A, Vertruyen B, Rikel MO, Lutterotti L, Pautrat A, Ouladdiaf B, Chateigner D. Preferred Orientation Contribution to the Anisotropic Normal State Resistivity in Superconducting Melt-Cast Processed Bi₂Sr₂CaCu₂O 8+δ. Materials (Basel) 2017; 10:E534. [PMID: 28772894 PMCID: PMC5459035 DOI: 10.3390/ma10050534] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 05/06/2017] [Accepted: 05/12/2017] [Indexed: 11/16/2022]
Abstract
We describe how the contribution of crystallographic texture to the anisotropy of the resistivity of polycrystalline samples can be estimated by averaging over crystallographic orientations through a geometric mean approach. The calculation takes into account the orientation distribution refined from neutron diffraction data and literature values for the single crystal resistivity tensor. The example discussed here is a melt-cast processed Bi₂Sr₂CaCu₂O8+δ (Bi-2212) polycrystalline tube in which the main texture component is a <010> fiber texture with relatively low texture strength. Experimentally-measured resistivities along the longitudinal, radial, and tangential directions of the Bi-2212 tube were compared to calculated values and found to be of the same order of magnitude. Calculations for this example and additional simulations for various texture strengths and single crystal resistivity anisotropies confirm that in the case of highly anisotropic phases such as Bi-2212, even low texture strengths have a significant effect on the anisotropy of the resistivity in polycrystalline samples.
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Affiliation(s)
- Aline Dellicour
- GREENMAT, CESAM Research Unit, Institute of Chemistry, University of Liege, Sart-Tilman, 4000 Liege, Belgium.
- Normandie Université, CRISMAT-ENSICAEN-UCN UMR 6508 CNRS, 6 Bd. Maréchal Juin, 14050 Caen, France.
| | - Benedicte Vertruyen
- GREENMAT, CESAM Research Unit, Institute of Chemistry, University of Liege, Sart-Tilman, 4000 Liege, Belgium.
| | - Mark O Rikel
- Nexans Superconductors, 30179 Hannover, Germany.
| | - Luca Lutterotti
- Department of Industrial Engineering, University of Trento, via sommarive, 9-38123 Trento, Italy.
| | - Alain Pautrat
- Normandie Université, CRISMAT-ENSICAEN-UCN UMR 6508 CNRS, 6 Bd. Maréchal Juin, 14050 Caen, France.
| | - Bachir Ouladdiaf
- Institut-Laue-Langevin, Bd. Jules Horowitz, 38042 Grenoble, France.
| | - Daniel Chateigner
- Normandie Université, CRISMAT-ENSICAEN-UCN UMR 6508 CNRS, 6 Bd. Maréchal Juin, 14050 Caen, France.
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20
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Blazquez-Alcover I, Huvé M, Mocuta C, Thiaudière D, Roussel P, Pautrat A, Mentré O, Daviero-Minaud S. Original positively charged nanoflakes by liquid exfoliation of layered oxybromide cobaltites. CrystEngComm 2017. [DOI: 10.1039/c6ce02248k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Abstract
New ferroelectric layered materials were found in the pseudobinary system Bi5Nb3O15-ABi2Nb2O9 (A= Ba, Sr and Pb). Preliminary observations made by transmission electron microscopy indicate that these compounds exhibit a complex incommensurately modulated structure. A (3 + 1)D structural model is obtained using ab initio phasing by charge flipping based on the analysis of precession electron diffraction tomography data. The (3 + 1)D structure is further validated by a refinement against neutron powder diffraction. These materials possess a layered structure with discontinuous [Bi2O2] slabs and perovskite blocks. While these structural units are characteristics of Aurivillius phases, the existence of periodic crystallographic shear planes offers strong similarities with collapsed or stairlike structures known in high-Tc superconductors and related compounds. Using dielectric spectroscopy, we study the phase transitions of these new layered materials. For A = Ba and Sr, a Vögel-Fulcher-like behavior characteristic of the so-called relaxor ferroelectrics is observed and compared to "canonical" relaxors. For A = Sr, the absence of a Burns temperature separated from the freezing temperature appears as a rather unusual behavior.
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Affiliation(s)
- Gwladys Steciuk
- Laboratoire CRISMAT, UMR CNRS 6508, ENSICAEN, 6 Bd Maréchal Juin, F-14050 Caen Cedex 4, France
| | - Philippe Boullay
- Laboratoire CRISMAT, UMR CNRS 6508, ENSICAEN, 6 Bd Maréchal Juin, F-14050 Caen Cedex 4, France
| | - Alain Pautrat
- Laboratoire CRISMAT, UMR CNRS 6508, ENSICAEN, 6 Bd Maréchal Juin, F-14050 Caen Cedex 4, France
| | - Nicolas Barrier
- Laboratoire CRISMAT, UMR CNRS 6508, ENSICAEN, 6 Bd Maréchal Juin, F-14050 Caen Cedex 4, France
| | - Vincent Caignaert
- Laboratoire CRISMAT, UMR CNRS 6508, ENSICAEN, 6 Bd Maréchal Juin, F-14050 Caen Cedex 4, France
| | - Lukas Palatinus
- Institute of Physics, Czech Academy of Sciences , Na Slovance 2, 182 21 Prague, Czechia
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David R, Pautrat A, Kabbour H, Mentré O. Common Building Motifs in Ba2Fe3(PO4)4·2H2O, BaFe3(PO4)3, and Na3Fe3(PO4)4: Labile Fe2+/Fe3+ Ordering and Charge-Dependent Magnetism. Inorg Chem 2016; 55:4354-61. [DOI: 10.1021/acs.inorgchem.6b00071] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rénald David
- Université Lille, CNRS, Centrale Lille, ENSCL, Université Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille, France
- Laboratoire de Réactivité et Chimie des Solides, CNRS
UMR 7314, Université Picardie Jules Verne, 33 Rue Saint Leu, 80039 Amiens Cedex, France
| | - Alain Pautrat
- Laboratoire CRISMAT, CNRS UMR 6508, ENSICAEN et Université de Caen, 6 Boulevard Maréchal Juin, F-14050 Caen 4, France
| | - Houria Kabbour
- Université Lille, CNRS, Centrale Lille, ENSCL, Université Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille, France
| | - Olivier Mentré
- Université Lille, CNRS, Centrale Lille, ENSCL, Université Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille, France
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Rotella H, Pautrat A, Copie O, Boullay P, David A, Mercey B, Morales M, Prellier W. Kondo effect goes anisotropic in vanadate oxide superlattices. J Phys Condens Matter 2015; 27:435601. [PMID: 26444931 DOI: 10.1088/0953-8984/27/43/435601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We study the transport properties in SrVO3/LaVO3 (SVO/LVO) superlattices deposited on SrTiO3 (STO) substrates. We show that the electronic conduction occurs in the metallic LVO layers with a galvanomagnetism typical of a 2D Fermi surface. In addition, a Kondo-like component appears in both the thermal variation of resistivity and the magnetoresistance. Surprisingly, in this system where the STO interface does not contribute to the measured conduction, the Kondo correction is strongly anisotropic. We show that the growth temperature allows a direct control of this contribution. Finally, the key role of vanadium mixed valency stabilized by oxygen vacancies is enlightened.
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Affiliation(s)
- H Rotella
- Laboratoire CRISMAT, CNRS UMR 6508, ENSICAEN et Université de Caen, 6 Bd Maréchal Juin, 14050 Caen Cedex 4, France
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24
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Delacotte C, Pérez O, Pautrat A, Berthebaud D, Hébert S, Suard E, Pelloquin D, Maignan A. Magnetodielectric Effect in Crystals of the Noncentrosymmetric CaOFeS at Low Temperature. Inorg Chem 2015; 54:6560-5. [DOI: 10.1021/acs.inorgchem.5b00879] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Charlène Delacotte
- Laboratoire CRISMAT ENSICAEN, UMR CNRS 6508, 6 Boulevard du Maréchal Juin, 14050 Caen Cedex 04, France
| | - Olivier Pérez
- Laboratoire CRISMAT ENSICAEN, UMR CNRS 6508, 6 Boulevard du Maréchal Juin, 14050 Caen Cedex 04, France
| | - Alain Pautrat
- Laboratoire CRISMAT ENSICAEN, UMR CNRS 6508, 6 Boulevard du Maréchal Juin, 14050 Caen Cedex 04, France
| | - David Berthebaud
- Laboratoire CRISMAT ENSICAEN, UMR CNRS 6508, 6 Boulevard du Maréchal Juin, 14050 Caen Cedex 04, France
| | - Sylvie Hébert
- Laboratoire CRISMAT ENSICAEN, UMR CNRS 6508, 6 Boulevard du Maréchal Juin, 14050 Caen Cedex 04, France
| | - Emmanuelle Suard
- Institut Laue-Langevin (ILL), 71 avenue des Martyrs, 38042 Grenoble Cedex 9, France
| | - Denis Pelloquin
- Laboratoire CRISMAT ENSICAEN, UMR CNRS 6508, 6 Boulevard du Maréchal Juin, 14050 Caen Cedex 04, France
| | - Antoine Maignan
- Laboratoire CRISMAT ENSICAEN, UMR CNRS 6508, 6 Boulevard du Maréchal Juin, 14050 Caen Cedex 04, France
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Rotella H, Copie O, Steciuk G, Ouerdane H, Boullay P, Roussel P, Morales M, David A, Pautrat A, Mercey B, Lutterotti L, Chateigner D, Prellier W. Structural analysis of strained LaVO3 thin films. J Phys Condens Matter 2015; 27:175001. [PMID: 25765433 DOI: 10.1088/0953-8984/27/17/175001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
While structure refinement is routinely achieved for simple bulk materials, the accurate structural determination still poses challenges for thin films due on the one hand to the small amount of material deposited on the thicker substrate and, on the other hand, to the intricate epitaxial relationships that substantially complicate standard x-ray diffraction analysis. Using both electron and x-ray diffraction, we analyze the crystal structure of epitaxial LaVO3 thin films grown on (1 0 0)-oriented SrTiO3. Transmission electron microscopy study reveals that the thin films are epitaxially grown on SrTiO3 and points to the presence of 90° oriented domains. The mapping of the reciprocal space obtained by high resolution x-ray diffraction permits refinement of the lattice parameters. We finally deduce that strain accommodation imposes a monoclinic structure onto the LaVO3 film. The reciprocal space maps are numerically processed and the extracted data computed to refine the atomic positions, which are compared to those obtained using precession electron diffraction tomography.
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Affiliation(s)
- H Rotella
- Laboratoire CRISMAT, UMR 6508 CNRS, ENSICAEN et Université de Caen Basse Normandie, 6 Boulevard Maréchal Juin, F-14050 Caen, France
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Rotella H, Copie O, Pautrat A, Boullay P, David A, Pelloquin D, Labbé C, Frilay C, Prellier W. Two components for one resistivity in LaVO3/SrTiO3 heterostructure. J Phys Condens Matter 2015; 27:095603. [PMID: 25688927 DOI: 10.1088/0953-8984/27/9/095603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A series of 100 nm LaVO3 thin films have been synthesized on (0 0 1)-oriented SrTiO3 substrates using the pulsed laser deposition technique, and the effects of growth temperature are analyzed. Transport properties reveal a large electronic mobility and a non-linear Hall effect at low temperature. In addition, a cross-over from a semiconducting state at high-temperature to a metallic state at low-temperature is observed, with a clear enhancement of the metallic character as the growth temperature increases. Optical absorption measurements combined with the two-bands analysis of the Hall effect show that the metallicity is induced by the diffusion of oxygen vacancies in the SrTiO3 substrate. These results allow us to understand that the film/substrate heterostructure behaves as an original semiconducting-metallic parallel resistor, and electronic transport properties are consistently explained.
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Affiliation(s)
- H Rotella
- Laboratoire CRISMAT, CNRS UMR 6508, ENSICAEN et Université de Caen, 6 Bd Maréchal Juin, 14050 Caen Cedex 4, France. NUSNNI-NanoCore, National University of Singapore, 117411 Singapore
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David R, Kabbour H, Filimonov D, Huvé M, Pautrat A, Mentré O. Reversible Topochemical Exsolution of Iron in BaFe2+2(PO4)2. Angew Chem Int Ed Engl 2014; 53:13365-70. [DOI: 10.1002/anie.201404476] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 08/07/2014] [Indexed: 11/10/2022]
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David R, Kabbour H, Filimonov D, Huvé M, Pautrat A, Mentré O. Reversible Topochemical Exsolution of Iron in BaFe2+2(PO4)2. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201404476] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Pérez O, Kolincio K, Pautrat A. Phase transitions toward charge density wave in the m=11.5 Mono phosphate bronze. Acta Crystallogr A Found Adv 2014. [DOI: 10.1107/s2053273314098192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Mono Phosphate Tungsten Bronzes (MPTB), (PO2)4(WO3)2m (m ranging from 4 to 14), are a large family of conductors of low dimensionality[1]. Their structure may be described as a regular stacking of WO3-type slabs with a thickness function of m, joined by slices of tetrahedral PO4 phosphate. Successive Peierls transitions towards charge-density wave (CDW) or spin-density wave (SDW) states are observed below different critical temperatures (TC1, TC2 ...). Structural transitions toward incommensurate modulated phases are associated with these complex electronic states. Recently an original member of MPTB, the member m=11.5 with formula (PO2)4(WO3)11(WO3)12, resulting in a regular intergrowth between m=11 and m=12 member, has been synthetized. An accurate investigation of the reciprocal space versus the temperature using single crystal X-ray diffraction shows the existence of two phase transitions at Tc1=4300C and Tc2=2800C. The ground state structure may be described with the following cell parameters a=5.3431(7) b=6.5901(9) c=40.884(6) α=93.096(2) β=93.734(2) γ=90.000(2) and the SG P-1. Both transitions associated with the occurrence of CDW are characterized by the appearance of modulation vectors (q1 and q2 associated to Tc1 and Tc2 respectively) and an increasing of the dimension of the superspace group (see figure 1). A structural study of the m=11.5 member is performed above Tc1 and below Tc1 and Tc2; an interpretation of the CDW state is then proposed. The evolution of the intensity of the satellite and main reflections around Tc1 and Tc2 is analyzed for characterizing the order parameter of the transitions. Finally, resistivity and magnetoresitance measurements of a large single crystal sample of m=11.5 MPTB are performed in a temperature interval from 2K to 300K. These measures are revealing at ~50K a possible SDW transition due to electron-electron interactions playing significant role in that material[2]. Further neutron diffraction experiment at very low temperature shall be performed to clarify this point.
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Dellicour A, Pautrat A, Vertruyen B, Rikel M, Lutterotti L, Chateigner D. Anisotropic resistivity tensor of melt-cast Bi2212 superconductors from QTA. Acta Crystallogr A Found Adv 2014. [DOI: 10.1107/s2053273314092730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Bi2Sr2CaCu2O8+δ HTSC superconductor is characterized by a very strong normal-state resistivity anisotropy, with ρc/ρab typically above 10E4. The aim of this study is to use Quantitative Texture Analysis from x-ray diffraction measurements to estimate the orientation effect on the anisotropic macroscopic resistivity in melt-cast bulk Bi2Sr2CaCu2O8+δ superconductors. Our approach uses the geometric mean [1] of the single crystal resistivity tensor weighted by the Orientation Distribution Function (ODF) to quantitatively estimate the macroscopic resistivity tensor of the samples. The ODF is obtained from x-ray Combined Analysis [2], using the E-WIMV algorithm of the MAUD software. The GMA applies to the rank-two resistivity tensor of the orthorhombic space group considered tetragonal due to the small difference of a- and b-axes of the phase, with only two independent tensor components. We relate a relatively good agreement between measured and calculated macroscopic anisotropic resistivity ratios. Even with ρc/ρab between 10E4 and 10E5 for Bi2212 at room temperature in single crystals [3], we experiment macroscopic ratio in our bulk samples of around only 2. This small ratio is explained by the weak planar- or fiber-like (Figure) texture achieved in the melt-cast samples, characterized by maxima of orientation distributions not larger than 10 mrd. Calculated resistivities, based on homogeneous crystallites, perfect grain boundaries and no secondary phases, are 10 times larger than the observed ones. This suggests that the observed minor phases positively affect conductive pathways between grains. Calculated and measured anisotropic resistive ratios are coherent with one another, and Combined Analysis gives good predictions of these former.
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Pautrat A, Brûlet A. Temperature dependence of clusters with attracting vortices in superconducting niobium studied by neutron scattering. J Phys Condens Matter 2014; 26:232201. [PMID: 24810802 DOI: 10.1088/0953-8984/26/23/232201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We investigated the intermediate mixed state of a superconducting niobium sample using very small angle neutron scattering. We show that this state is stabilized through a sequence where a regular vortex lattice appears, which then coexists with vortex clusters before vanishing at low temperature. Vortices in clusters have a constant periodicity regardless of the applied field and exhibit a temperature dependence close to the one of the penetration depth. The clusters disappear in the high temperature limit. All the results agree with an explanation in terms of vortex attraction due to non-local effects and indicate a negligible role for pinning. Phase coexistence between the Abrikosov vortex lattice and vortex clusters is reported, showing the first-order nature of the boundary line.
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Affiliation(s)
- A Pautrat
- Laboratoire CRISMAT, UMR 6508 CNRS-ENSI Caen, 6 Bd Maréchal Juin, 14050 Caen, France
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David R, Kabbour H, Pautrat A, Touati N, Whangbo MH, Mentré O. Two-Orbital Three-Electron Stabilizing Interaction for Direct Co 2+As 3+Bonds involving Square-Planar CoO 4in BaCoAs 2O 5. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201311183] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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David R, Kabbour H, Pautrat A, Touati N, Whangbo MH, Mentré O. Two-Orbital Three-Electron Stabilizing Interaction for Direct Co2+As3+Bonds involving Square-Planar CoO4in BaCoAs2O5. Angew Chem Int Ed Engl 2014; 53:3111-4. [DOI: 10.1002/anie.201311183] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Indexed: 11/10/2022]
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Copie O, Rotella H, Boullay P, Morales M, Pautrat A, Janolin PE, Infante IC, Pravathana D, Lüders U, Prellier W. Structure and magnetism of epitaxial PrVO3 films. J Phys Condens Matter 2013; 25:492201. [PMID: 24214665 DOI: 10.1088/0953-8984/25/49/492201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The interplay between charge, spin, orbital and lattice degrees of freedom in transition metal oxides has motivated extensive research aiming to understand the coupling phenomena in these multifunctional materials. Among them, rare earth vanadates are Mott insulators characterized by spin and orbital orderings strongly influenced by lattice distortions. Using epitaxial strain as a means to tailor the unit cell deformation, we report here on the first thin films of PrVO3 grown on (001)-oriented SrTiO3 substrate by pulsed laser deposition. An extensive structural characterization of the PrVO3 films, combining x-ray diffraction and high-resolution transmission electron microscopy studies, reveals the presence of oriented domains and a unit cell deformation tailored by the growth conditions. We have also investigated the physical properties of the PrVO3 films. We show that, while PrVO3 exhibits an insulating character, magnetic measurements indicate low-temperature hard-ferromagnetic behavior below 80 K. We discuss these properties in view of the thin-film structure.
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Affiliation(s)
- O Copie
- Laboratoire CRISMAT, CNRS-ENSICAEN and Université de Caen Basse Normandie (UMR 6508), 6 boulevard du Maréchal Juin, F-14050 Caen Cedex, France
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David R, Kabbour H, Pautrat A, Colis S, Mentré O. Crystal chemistry of new low-dimensional ferromagnetic oxides: influence of aperiodicity and cationic ordering on the magnetic properties. Acta Crystallogr A 2013. [DOI: 10.1107/s0108767313099121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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36
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David R, Pautrat A, Filimonov D, Kabbour H, Vezin H, Whangbo MH, Mentré O. Across the structural re-entrant transition in BaFe2(PO4)2: influence of the two-dimensional ferromagnetism. J Am Chem Soc 2013; 135:13023-9. [PMID: 23968376 DOI: 10.1021/ja404697b] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BaFe2(PO4)2 was recently prepared by hydrothermal synthesis and identified as the first two-dimensional (2D) Ising ferromagnetic oxide, in which honeycomb layers made up of edge-sharing FeO6 octahedra containing high-spin Fe(2+) ions (S = 2) are isolated by PO4 groups and Ba(2+) cations. BaFe2(PO4)2 has a trigonal R-3 structure at room temperature but adopts a triclinic P-1 structure below 140 K due to the Jahn-Teller (JT) instability arising from the (t2g)(4)(eg)(2) configuration. The triclinic crystal structure was refined to find significantly distorted Fe(2+)O6 octahedra in the honeycomb layers while the distortion amplitude QJT was estimated to 0.019 Å. The JT stabilization energy is estimated to be ∼7 meV per formula unit by DFT calculations. Below ∼70 K, very close to the ferromagnetic transition temperature Tc = 65.5 K, the structure of BaFe2(PO4)2 returns to a trigonal R-3 structure in the presence of significant ferromagnetic domains. This rare re-entrant structural transition is accompanied by a discontinuous change in the quadrupolar splitting of Fe(2+), as determined by Mössbauer spectroscopy. EPR measurements show the presence of magnetic domains well above Tc , as expected for a ferromagnetic 2D Ising system, and support that the magnetism of BaFe2(PO4)2 is uniaxial (g⊥ = 0).
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Affiliation(s)
- Rénald David
- Université Lille Nord de France, UCCS, UMR-CNRS 8181, ENSCL-USTL, Villeneuve d'Ascq, France
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Abstract
In this paper, we present the phase diagram and magnetic properties of the layered Co(2+)-based compounds of formula Ba(CoPO4)2 for which the rhombohedral γ form is well-known for its quasi-2D XY topology that is responsible for magnetization steps. The structural resolution of the new, room temperature-stable monoclinic α form shows similitude with the hydrated homologue Ba(CoPO4)2·H2O and consists of the stacking between [CoPO4](-) sheets with chain subunits. We show by means of high temperature powder XRD and thermal analyses that the α form transforms into several polymorphs also exhibiting layered architectures upon heating. Three reversible transitions at 773, 893, and 993 K were observed from DTA which allowed us to define several forms as follows: α → α' → α″ → β. The crystallographic relationships between the several polymorphs and hydrate analogue are discussed. The α' and α″ cell parameters involve a direct relationship with the α form, whereas the trigonal β phase was fully solved and found isomorphic with the compounds CaZn2P2O8 and BaAl2Si2O8. The magnetic study of the α form shows an antiferromagnetic ordering at T(N) = 17 K, with spins canting below T(N). Then, the analysis of the magnetic interactions paths occurring within the layers evidence superexchange paths and additional supersuperexchange paths between the chains. This scheme leads to a hexagonal frustrated topology responsible for the canted spin structure in a 2D-topology of anisotropic Co(2+) magnetic ions.
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Affiliation(s)
- Rénald David
- Université Lille Nord de France, UMR 8181 CNRS, Unité de Catalyse et de Chimie du Solide (UCCS USTL), F-59655 Villeneuve d'Ascq, France
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El Hafid H, Velázquez M, Pérez O, El Jazouli A, Pautrat A, Decourt R, Véron E, Viraphong O, Delmas C. On the synthesis, characterization and magnetic properties of two new phases discovered in the PbO–Fe2O3–P2O5 system. J SOLID STATE CHEM 2013. [DOI: 10.1016/j.jssc.2013.03.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Ujić P, de Oliveira Santos F, Lewitowicz M, Achouri NL, Assié M, Bastin B, Borcea C, Borcea R, Buta A, Coc A, de France G, Kamalou O, Kiener J, Lepailleur A, Meot V, Pautrat A, Saint Laurent MG, Sorlin O, Stanoiu M, Tatischeff V. Search for superscreening effects in a superconductor. Phys Rev Lett 2013; 110:032501. [PMID: 23373914 DOI: 10.1103/physrevlett.110.032501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Indexed: 06/01/2023]
Abstract
The decay of (19)O(β(-)) and (19)Ne(β(+)) implanted in niobium in its superconducting and metallic phases was measured using purified radioactive beams produced by the SPIRAL GANIL facility. Half-lives and branching ratios measured in the two phases are consistent within a 1σ error bar. This measurement casts strong doubts on the predicted strong electron screening in a superconductor, the so-called superscreening. The measured difference in screening potential energy is 110(90) eV for (19)Ne and 400(320) eV for (19)O. Precise determinations of the half-lives were obtained for (19)O, 26.476(9) s, and for (19)Ne, 17.254(5) s.
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Affiliation(s)
- P Ujić
- GANIL CEA/DSM-CNRS/IN2P3, Caen, France
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Kabbour H, David R, Pautrat A, Koo HJ, Whangbo MH, André G, Mentré O. A Genuine Two-Dimensional Ising Ferromagnet with Magnetically Driven Re-entrant Transition. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201205843] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Kabbour H, David R, Pautrat A, Koo HJ, Whangbo MH, André G, Mentré O. A Genuine Two-Dimensional Ising Ferromagnet with Magnetically Driven Re-entrant Transition. Angew Chem Int Ed Engl 2012; 51:11745-9. [DOI: 10.1002/anie.201205843] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 08/31/2012] [Indexed: 11/11/2022]
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Rueff JM, Perez O, Pautrat A, Barrier N, Hix GB, Hernot S, Couthon-Gourvès H, Jaffrès PA. Structural study of hydrated/dehydrated manganese thiophene-2,5-diphosphonate metal organic frameworks, Mn2(O3P-C4H2S-PO3)·2H2O. Inorg Chem 2012; 51:10251-61. [PMID: 22994272 DOI: 10.1021/ic301187y] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Synthesis of thiophene-2,5-diphosphonic acid 2 is reported, and its use for synthesis of the original pristine materials Mn(2)(O(3)P-C(4)H(2)S-PO(3))·2H(2)O 3 is reported. The structure of material 3 has been fully resolved from single-crystal X-ray diffraction. Mn(2)(O(3)P-C(4)H(2)S-PO(3))·2H(2)O 3 crystallizes in a monoclinic cell (space group P2) with the following parameters: a = 11.60(1) Å, b = 4.943(5) Å, c = 19.614(13) Å, β = 107.22°. A noticeable feature of the structure of compound 3 is the orientation of the thiophene heterocycles that adopt two different orientations in two successive layers (along c). Thermal analysis of compound 3 indicates that the water molecules are easily removed from 160 to 230 °C while the dehydrated structure is stable up to 500 °C. The dehydrated compound obtained from 3 can be rehydrated to give the polymorphic compound Mn(2)(O(3)P-C(4)H(2)S-PO(3))·2H(2)O 4, which crystallizes in an orthorhombic cell (space group Pnam) with the following parameters: a = 7.5359(3) Å, b = 7.5524(3) Å, c = 18.3050(9) Å. The main difference between the structures of 3 and 4 arises from both the orientation of the thiophene rings (herringbone-type organization in 4) and the structure of the inorganic layers. The thiophene-2,5-diphosphonic acid moieties engaged in materials 3 and 4 adopt a different orientation likely due to rotation around the P-C bonds and via the dehydrated state 5, which is likely more flexible than the hydrated states. Study of the magnetic properties performed on compound 3 and 4 and on the dehydrated compounds Mn(2)(O(3)P-C(4)H(2)S-PO(3)) 5 complemented by the structural study has permitted us to characterize the antiferromagnetic ground state of sample 3, a weak ferromagnetic component in sample 4, and complete paramagnetic behavior in sample 5.
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Affiliation(s)
- Jean-Michel Rueff
- CRISMAT, UMR CNRS 6508, ENSICAEN, Université de Caen Basse-Normandie, 6 Boulevard du Maréchal Juin, 14050 Caen, France.
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El Hafid H, Velázquez M, Pérez O, El Jazouli A, Pautrat A, Decourt R, Veber P, Viraphong O, Delmas C. Crystal Growth and Structure of the New Ferrimagnetic Oxyphosphate PbFe
3
O(PO
4
)
3. Eur J Inorg Chem 2011. [DOI: 10.1002/ejic.201100815] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Hassan El Hafid
- CNRS, Université de Bordeaux, ICMCB, 87 avenue du Dr. A. Schweitzer, 33608 Pessac cedex, France
| | - Matias Velázquez
- CNRS, Université de Bordeaux, ICMCB, 87 avenue du Dr. A. Schweitzer, 33608 Pessac cedex, France
| | - Olivier Pérez
- Laboratoire de Cristallographie et Sciences des Matériaux, UMR 6508 CNRS/Université de Caen, 6 Boulevard du Maréchal Juin, 14050 Caen cedex 04, France
| | - Abdelaziz El Jazouli
- Laboratoire de Chimie des Matériaux Solides, URAC 17,Université Hassan II Mohammedia, Faculté des Sciences Ben M'Sik, Casablanca, Morocco, Fax: +33‐5‐40‐00‐27‐61
| | - Alain Pautrat
- Laboratoire de Cristallographie et Sciences des Matériaux, UMR 6508 CNRS/Université de Caen, 6 Boulevard du Maréchal Juin, 14050 Caen cedex 04, France
| | - Rodolphe Decourt
- CNRS, Université de Bordeaux, ICMCB, 87 avenue du Dr. A. Schweitzer, 33608 Pessac cedex, France
| | - Philippe Veber
- CNRS, Université de Bordeaux, ICMCB, 87 avenue du Dr. A. Schweitzer, 33608 Pessac cedex, France
| | - Oudomsack Viraphong
- CNRS, Université de Bordeaux, ICMCB, 87 avenue du Dr. A. Schweitzer, 33608 Pessac cedex, France
| | - Claude Delmas
- CNRS, Université de Bordeaux, ICMCB, 87 avenue du Dr. A. Schweitzer, 33608 Pessac cedex, France
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Pautrat A, Goupil C, Simon C, Charalambous D, Forgan EM, Lazard G, Mathieu P, Brûlet A. Distribution of transport current in a type-II superconductor studied by small-angle neutron scattering. Phys Rev Lett 2003; 90:087002. [PMID: 12633451 DOI: 10.1103/physrevlett.90.087002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2002] [Indexed: 05/24/2023]
Abstract
We report small-angle neutron scattering measurements on the vortex lattice in a PbIn polycrystal in the presence of an applied current. Using the rocking curves as a probe of the distribution of current in the sample, we observe that vortex pinning is due to the surface roughness. This leads to a surface current that persists in the flux-flow region. We show the influence of surface treatments on the distribution of this current.
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Affiliation(s)
- A Pautrat
- Laboratoire CRISMAT, UMR 6508 du CNRS et de l'ISMRA, 14050 CAEN, France
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Forgan EM, Kealey PG, Johnson ST, Pautrat A, Simon C, Lee SL, Aegerter CM, Cubitt R, Farago B, Schleger P. Measurement of vortex motion in a type-II superconductor: A novel use of the neutron spin-echo technique. Phys Rev Lett 2000; 85:3488-3491. [PMID: 11030928 DOI: 10.1103/physrevlett.85.3488] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2000] [Indexed: 05/23/2023]
Abstract
We have used the neutron spin-echo technique to measure the small energy change of neutrons which are diffracted by a moving vortex lattice in a low-pinning Nb-Ta superconducting sample. A transport current was passed in the mixed state to cause flux line movement. In the case of uniform motion, the flux velocity v(L) was given as expected by the values of electric and magnetic fields, via E = -v(L)wedgeB. We show that with a nonuniformly moving vortex lattice, one can measure the dispersion of the velocities, opening up new possibilities for investigating moving vortex lines.
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Affiliation(s)
- EM Forgan
- School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT United Kingdom
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