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N'Diaye A, Bordage A, Nataf L, Baudelet F, Moreno T, Bleuzen A. A cookbook for the investigation of coordination polymers by transition metal K-edge XMCD. JOURNAL OF SYNCHROTRON RADIATION 2021; 28:1127-1136. [PMID: 34212876 DOI: 10.1107/s1600577521004884] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 05/08/2021] [Indexed: 06/13/2023]
Abstract
In order to disentangle the physical effects at the origin of transition metal K-edge X-ray magnetic circular dichroism (XMCD) in coordination polymers and quantify small structural distortions from the intensity of these signals, a systematic investigation of Prussian blue analogs as model compounds is being conducted. Here the effects of the temperature and of the external magnetic field are tackled; none of these external parameters modify the shape of the XMCD signal but they both critically modify its intensity. The optimized experimental conditions, as well as a reliable and robust normalization procedure, could thus be determined for the study of the intrinsic parameters. Through an extended discussion on measurements on other XMCD-dedicated beamlines and for other coordination compounds, we finally provide new transition metal K-edge XMCD users with useful information to initiate and successfully carry out their projects.
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Affiliation(s)
- Adama N'Diaye
- ICMMO, Université Paris Saclay, CNRS, 15 rue Georges Clémenceau, 91405 Orsay, France
| | - Amélie Bordage
- ICMMO, Université Paris Saclay, CNRS, 15 rue Georges Clémenceau, 91405 Orsay, France
| | - Lucie Nataf
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, BP 48, 91192 Gif-sur-Yvette, France
| | - François Baudelet
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, BP 48, 91192 Gif-sur-Yvette, France
| | - Thierry Moreno
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, BP 48, 91192 Gif-sur-Yvette, France
| | - Anne Bleuzen
- ICMMO, Université Paris Saclay, CNRS, 15 rue Georges Clémenceau, 91405 Orsay, France
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2
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Poldi EHT, Escanhoela CA, Fonseca J, Eleotério MAS, Dos Reis RD, Lang JC, Haskel D, Souza-Neto NM. A versatile X-ray phase retarder for lock-in XMCD measurements. JOURNAL OF SYNCHROTRON RADIATION 2020; 27:1240-1246. [PMID: 32876599 DOI: 10.1107/s1600577520009558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 07/13/2020] [Indexed: 06/11/2023]
Abstract
X-ray magnetic circular dichroism (XMCD) is a technique commonly used to probe magnetic properties of materials with element and orbital selectivity, which requires the use of circularly polarized (CP) X-rays. It is possible to accomplish XMCD experiments with fixed CP and alternating the magnetic field orientation, but most reliable data are obtained when alternating the magnetization orientation and the polarization between right and left helicities. A versatile strategy has been developed to perform XMCD experiments using a hard X-ray quarter-wave plate, at both polychromatic dispersive and conventional monochromatic optics, in combination with synchronous data acquisition. The switching frequency waveform is fed into a lock-in amplifier to detect and amplify the XMCD signal. The results on a reference sample demonstrate an improvement in data quality and acquisition time. The instrumentation successfully generated 98% of CP X-rays switching the beam helicity at 13 Hz, with the possibility of faster helicity switching once it is installed at the new Brazilian fourth-generation source, SIRIUS.
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Affiliation(s)
- Eduardo H T Poldi
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Sao Paulo 13083-970, Brazil
| | - Carlos A Escanhoela
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Sao Paulo 13083-970, Brazil
| | - Jairo Fonseca
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Sao Paulo 13083-970, Brazil
| | - Marcos A S Eleotério
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Sao Paulo 13083-970, Brazil
| | - Ricardo D Dos Reis
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Sao Paulo 13083-970, Brazil
| | - Jonathan C Lang
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Daniel Haskel
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Narcizo M Souza-Neto
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Sao Paulo 13083-970, Brazil
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3
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Lahiri D, Dwivedi A, Vasanthi R, Jha SN, Garg N. First high-pressure XAFS results at the bending-magnet-based energy-dispersive XAFS beamline BL-8 at the Indus-2 synchrotron facility. JOURNAL OF SYNCHROTRON RADIATION 2020; 27:988-998. [PMID: 33566008 DOI: 10.1107/s1600577520006098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 05/04/2020] [Indexed: 06/12/2023]
Abstract
The static focusing optics of the existing energy-dispersive XAFS beamline BL-8 have been advantageously exploited to initiate diamond anvil cell based high-pressure XANES experiments at the Indus-2 synchrotron facility, India. In the framework of the limited photon statistics with the 2.5 GeV bending-magnet source, limited focusing optics and 4 mm-thick diamond windows of the sample cell, a (non-trivial) beamline alignment method for maximizing photon statistics at the sample position has been designed. Key strategies include the selection of a high X-ray energy edge, the truncation of the smallest achievable focal spot size to target size with a slit and optimization of the horizontal slit position for transmission of the desired energy band. A motor-scanning program for precise sample centering has been developed. These details are presented with rationalization for every step. With these strategies, Nb K-edge XANES spectra for Nb2O5 under high pressure (0-16.9 GPa) have been generated, reproducing the reported spectra for Nb2O5 under ambient conditions and high pressure. These first HPXANES results are reported in this paper. The scope of extending good data quality to the EXAFS range in the future is addressed. This work should inspire and guide future high-pressure XAFS experiments with comparable infrastructure.
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Affiliation(s)
- Debdutta Lahiri
- High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - Ashutosh Dwivedi
- Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - R Vasanthi
- High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - S N Jha
- Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - Nandini Garg
- High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
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4
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Hsieh S, Bhattacharyya P, Zu C, Mittiga T, Smart TJ, Machado F, Kobrin B, Höhn TO, Rui NZ, Kamrani M, Chatterjee S, Choi S, Zaletel M, Struzhkin VV, Moore JE, Levitas VI, Jeanloz R, Yao NY. Imaging stress and magnetism at high pressures using a nanoscale quantum sensor. Science 2019; 366:1349-1354. [DOI: 10.1126/science.aaw4352] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 11/06/2019] [Indexed: 01/19/2023]
Abstract
Pressure alters the physical, chemical, and electronic properties of matter. The diamond anvil cell enables tabletop experiments to investigate a diverse landscape of high-pressure phenomena. Here, we introduce and use a nanoscale sensing platform that integrates nitrogen-vacancy (NV) color centers directly into the culet of diamond anvils. We demonstrate the versatility of this platform by performing diffraction-limited imaging of both stress fields and magnetism as a function of pressure and temperature. We quantify all normal and shear stress components and demonstrate vector magnetic field imaging, enabling measurement of the pressure-driven α↔ϵ phase transition in iron and the complex pressure-temperature phase diagram of gadolinium. A complementary NV-sensing modality using noise spectroscopy enables the characterization of phase transitions even in the absence of static magnetic signatures.
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Affiliation(s)
- S. Hsieh
- Department of Physics, University of California, Berkeley, CA 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - P. Bhattacharyya
- Department of Physics, University of California, Berkeley, CA 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - C. Zu
- Department of Physics, University of California, Berkeley, CA 94720, USA
| | - T. Mittiga
- Department of Physics, University of California, Berkeley, CA 94720, USA
| | - T. J. Smart
- Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, USA
| | - F. Machado
- Department of Physics, University of California, Berkeley, CA 94720, USA
| | - B. Kobrin
- Department of Physics, University of California, Berkeley, CA 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - T. O. Höhn
- Department of Physics, University of California, Berkeley, CA 94720, USA
- Fakultät für Physik, Ludwig-Maximilians-Universität München, 80799 Munich, Germany
| | - N. Z. Rui
- Department of Physics, University of California, Berkeley, CA 94720, USA
| | - M. Kamrani
- Department of Aerospace Engineering, Iowa State University, Ames, IA 50011, USA
| | - S. Chatterjee
- Department of Physics, University of California, Berkeley, CA 94720, USA
| | - S. Choi
- Department of Physics, University of California, Berkeley, CA 94720, USA
| | - M. Zaletel
- Department of Physics, University of California, Berkeley, CA 94720, USA
| | - V. V. Struzhkin
- Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015, USA
| | - J. E. Moore
- Department of Physics, University of California, Berkeley, CA 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - V. I. Levitas
- Department of Aerospace Engineering, Iowa State University, Ames, IA 50011, USA
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA
- Ames Laboratory, Division of Materials Science and Engineering, Ames, IA 50011, USA
| | - R. Jeanloz
- Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, USA
| | - N. Y. Yao
- Department of Physics, University of California, Berkeley, CA 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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5
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Lesik M, Plisson T, Toraille L, Renaud J, Occelli F, Schmidt M, Salord O, Delobbe A, Debuisschert T, Rondin L, Loubeyre P, Roch JF. Magnetic measurements on micrometer-sized samples under high pressure using designed NV centers. Science 2019; 366:1359-1362. [DOI: 10.1126/science.aaw4329] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 11/06/2019] [Indexed: 01/24/2023]
Abstract
Pressure can be used to tune the interplay among structural, electronic, and magnetic interactions in materials. High pressures are usually applied in the diamond anvil cell, making it difficult to study the magnetic properties of a micrometer-sized sample. We report a method for spatially resolved optical magnetometry based on imaging a layer of nitrogen-vacancy (NV) centers created at the surface of a diamond anvil. We illustrate the method using two sets of measurements realized at room temperature and low temperature, respectively: the pressure evolution of the magnetization of an iron bead up to 30 gigapascals showing the iron ferromagnetic collapse and the detection of the superconducting transition of magnesium dibromide at 7 gigapascals.
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Affiliation(s)
- Margarita Lesik
- Laboratoire Aimé Cotton, CNRS, Univ. Paris-Sud, ENS Paris-Saclay, Université Paris-Saclay, 91405 Orsay Cedex, France
| | | | - Loïc Toraille
- Laboratoire Aimé Cotton, CNRS, Univ. Paris-Sud, ENS Paris-Saclay, Université Paris-Saclay, 91405 Orsay Cedex, France
| | | | | | - Martin Schmidt
- Laboratoire Aimé Cotton, CNRS, Univ. Paris-Sud, ENS Paris-Saclay, Université Paris-Saclay, 91405 Orsay Cedex, France
| | | | | | | | - Loïc Rondin
- Laboratoire Aimé Cotton, CNRS, Univ. Paris-Sud, ENS Paris-Saclay, Université Paris-Saclay, 91405 Orsay Cedex, France
| | | | - Jean-François Roch
- Laboratoire Aimé Cotton, CNRS, Univ. Paris-Sud, ENS Paris-Saclay, Université Paris-Saclay, 91405 Orsay Cedex, France
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6
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Torchio R, Mathon O, Pascarelli S. XAS and XMCD spectroscopies to study matter at high pressure: Probing the correlation between structure and magnetism in the 3d metals. Coord Chem Rev 2014. [DOI: 10.1016/j.ccr.2014.02.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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7
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Tromp M, Dent AJ, Headspith J, Easun TL, Sun XZ, George MW, Mathon O, Smolentsev G, Hamilton ML, Evans J. Energy dispersive XAFS: characterization of electronically excited states of copper(I) complexes. J Phys Chem B 2013; 117:7381-7. [PMID: 23718738 PMCID: PMC3748449 DOI: 10.1021/jp4020355] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Energy
dispersive X-ray absorption spectroscopy (ED-XAS), in which
the whole XAS spectrum is acquired simultaneously, has been applied
to reduce the real-time for acquisition of spectra of photoinduced
excited states by using a germanium microstrip detector gated around
one X-ray bunch of the ESRF (100 ps). Cu K-edge XAS was used to investigate
the MLCT states of [Cu(dmp)2]+ (dmp =2,9-dimethyl-1,10-phenanthroline)
and [Cu(dbtmp)2]+ (dbtmp =2,9-di-n-butyl-3,4,7,8-tetramethyl-1,10-phenanthroline) with the excited
states created by excitation at 450 nm (10 Hz). The decay of the longer
lived complex with bulky ligands, was monitored for up to 100 ns.
DFT calculations of the longer lived MLCT excited state of [Cu(dbp)2]+ (dbp =2,9-di-n-butyl-1,10-phenanthroline)
with the bulkier diimine ligands, indicated that the excited state
behaves as a Jahn–Teller distorted Cu(II) site, with the interligand
dihedral angle changing from 83 to 60° as the tetrahedral coordination
geometry flattens and a reduction in the Cu–N distance of 0.03
Å.
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Affiliation(s)
- Moniek Tromp
- School of Chemistry, University of Southampton, Southampton, SO17 1BE, UK
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8
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Torchio R, Kvashnin YO, Pascarelli S, Mathon O, Marini C, Genovese L, Bruno P, Garbarino G, Dewaele A, Occelli F, Loubeyre P. X-ray magnetic circular dichroism measurements in Ni up to 200 GPa: resistant ferromagnetism. PHYSICAL REVIEW LETTERS 2011; 107:237202. [PMID: 22182121 DOI: 10.1103/physrevlett.107.237202] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Indexed: 05/31/2023]
Abstract
The structural stability of fcc Ni over a very large pressure range offers a unique opportunity to experimentally investigate how magnetism is modified by simple compression. K-edge x-ray magnetic circular dichroism (XMCD) shows that fcc Ni is ferromagnetic up to 200 GPa, contradicting recent predictions of an abrupt transition to a paramagnetic state at 160 GPa. Density functional theory calculations point out that the pressure evolution of the K-edge XMCD closely follows that of the p projected orbital moment rather than that of the total spin moment. The disappearance of magnetism in Ni is predicted to occur above 400 GPa.
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Affiliation(s)
- R Torchio
- European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, BP220, 38043 Grenoble Cedex, France
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9
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Strohm C, Perrin F, Dominguez MC, Headspith J, van der Linden P, Mathon O. Multi-frame acquisition scheme for efficient energy-dispersive X-ray magnetic circular dichroism in pulsed high magnetic fields at the Fe K-edge. JOURNAL OF SYNCHROTRON RADIATION 2011; 18:224-228. [PMID: 21335909 PMCID: PMC3267639 DOI: 10.1107/s090904951100080x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 01/06/2011] [Indexed: 05/30/2023]
Abstract
Using a fast silicon strip detector, a multi-frame acquisition scheme was implemented to perform energy-dispersive X-ray magnetic circular dichroism at the iron K-edge in pulsed high magnetic fields. The acquisition scheme makes use of the entire field pulse. The quality of the signal obtained from samples of ferrimagnetic erbium iron garnet allows for quantitative evaluation of the signal amplitude. Below the compensation point, two successive field-induced phase transitions and the reversal of the net magnetization of the iron sublattices in the intermediate phase were observed.
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Affiliation(s)
- Cornelius Strohm
- European Synchrotron Radiation Facility, 6 rue Jules Horowitz, 38043 Grenoble, France.
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10
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Cezar JC, Souza-Neto NM, Piamonteze C, Tamura E, Garcia F, Carvalho EJ, Neueschwander RT, Ramos AY, Tolentino HCN, Caneiro A, Massa NE, Martinez-Lope MJ, Alonso JA, Itié JP. Energy-dispersive X-ray absorption spectroscopy at LNLS: investigation on strongly correlated metal oxides. JOURNAL OF SYNCHROTRON RADIATION 2010; 17:93-102. [PMID: 20029117 DOI: 10.1107/s0909049509041119] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2009] [Accepted: 10/08/2009] [Indexed: 05/28/2023]
Abstract
An energy-dispersive X-ray absorption spectroscopy beamline mainly dedicated to X-ray magnetic circular dichroism (XMCD) and material science under extreme conditions has been implemented in a bending-magnet port at the Brazilian Synchrotron Light Laboratory. Here the beamline technical characteristics are described, including the most important aspects of the mechanics, optical elements and detection set-up. The beamline performance is then illustrated through two case studies on strongly correlated transition metal oxides: an XMCD insight into the modifications of the magnetic properties of Cr-doped manganites and the structural deformation in nickel perovskites under high applied pressure.
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Affiliation(s)
- Júlio C Cezar
- Laboratório Nacional de Luz Síncrotron - LNLS, CP6192, 13084-971 Campinas, SP, Brazil
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11
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Subías G, Cuartero V, García J, Blasco J, Mathon O, Pascarelli S. Pressure-induced magnetic transition in Fe3O4and CoFe2O4spinels. ACTA ACUST UNITED AC 2009. [DOI: 10.1088/1742-6596/190/1/012089] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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12
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Baudelet F, Mathon O, Itié JP, Polian A, Kappler JP, Pascarelli S. Magnetic and crystallographic characterization of Pt(3)Mn(x)Cr(1-x) by XMCD and x-ray diffraction. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:346003. [PMID: 21715793 DOI: 10.1088/0953-8984/21/34/346003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have performed XMCD and diffraction measurements on the Pt(3)Mn(x)Cr(1-x) alloy, which show that the magnetization of Pt is independently influenced by the Mn or Cr 3d orbital. We find that the magnetic moment on Pt, and its decomposition into spin and orbital components, is uniquely determined by the relative number of Mn and Cr neighbors. We then investigate the effect of pressure on the magnetization of Pt in the Pt(3)Mn(0.5)Cr(0.5) alloy. Our high pressure data enable us to conclude that at 14 GPa the spin and orbital polarization of the Pt 5d band are augmented by about 70%, with no interaction between them.
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Affiliation(s)
- F Baudelet
- IMPMC, CNRS UMR 7590, Université Pierre et Marie Curie Paris6, 140 rue de Lourmel, 75015 Paris, France. Synchrotron-SOLEIL, L'Orme des Merisiers, 91192 Gif-sur-Yvette, France
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13
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Ding Y, Haskel D, Ovchinnikov SG, Tseng YC, Orlov YS, Lang JC, Mao HK. Novel pressure-induced magnetic transition in magnetite (Fe3O4). PHYSICAL REVIEW LETTERS 2008; 100:045508. [PMID: 18352301 DOI: 10.1103/physrevlett.100.045508] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2007] [Revised: 11/13/2007] [Indexed: 05/26/2023]
Abstract
Fe K-edge x-ray magnetic circular dichroism of magnetite (Fe3O4) powders was measured with synchrotron radiation under variable pressure and temperature conditions in diamond anvil cell. The magnetic dichroism was observed to decrease discontinuously by approximately 50% between 12 and 16 GPa, independent of temperature. The magnetic transition is attributed to a high-spin to intermediate-spin transition of Fe2+ ions in the octahedral sites and could account for previously observed structural and electrical anomalies in magnetite at this pressure range. The interpretation of x-ray magnetic circular dichroism data is supported by x-ray emission spectroscopy and theoretical cluster calculations.
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Affiliation(s)
- Yang Ding
- HPSynC, Carnegie Institution of Washington, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
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14
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Pascarelli S, Ruffoni MP, Trapananti A, Mathon O, Aquilanti G, Ostanin S, Staunton JB, Pettifer RF. Effect of pressure on magnetoelastic coupling in 3d metal alloys studied with x-ray absorption spectroscopy. PHYSICAL REVIEW LETTERS 2007; 99:237204. [PMID: 18233406 DOI: 10.1103/physrevlett.99.237204] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Indexed: 05/25/2023]
Abstract
Using x-ray absorption spectroscopy, we have studied the effect of pressure on femtometer-scale bond strain due to anisotropic magnetostriction in a thin FeCo film. At 7 GPa local magnetostrictive strain is found to be larger than at ambient, in agreement with spin-polarized ab initio electronic structure calculations, but contrary to the expected effect of compression on bond stiffness. The availability of high pressure data on local magnetostrictive strain opens new capabilities for validating theoretical predictions and can lead to the development of materials with the desired properties.
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Affiliation(s)
- S Pascarelli
- European Synchrotron Radiation Facility, 6 rue Jules Horowitz, 38043 Grenoble, France
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15
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Haskel D, Tseng YC, Lang JC, Sinogeikin S. Instrument for x-ray magnetic circular dichroism measurements at high pressures. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2007; 78:083904. [PMID: 17764332 DOI: 10.1063/1.2773800] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
An instrument has been developed for x-ray magnetic circular dichroism (XMCD) measurements at high pressures and low temperatures. This instrument couples a nonmagnetic copper-beryllium diamond anvil cell featuring perforated diamonds with a helium flow cryostat and an electromagnet. The applied pressure can be controlled in situ using a gas membrane and calibrated using Cu K-edge x-ray absorption fine structure measurements. The performance of this instrument was tested by measuring the XMCD spectra of the Gd(5)Si(2)Ge(2) giant magnetocaloric material.
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Affiliation(s)
- D Haskel
- Magnetic Materials Group, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA.
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16
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Pettifer RF, Mathon O, Pascarelli S, Cooke MD, Gibbs MRJ. Measurement of femtometre-scale atomic displacements by X-ray absorption spectroscopy. Nature 2005; 435:78-81. [PMID: 15875018 DOI: 10.1038/nature03516] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2004] [Accepted: 03/04/2005] [Indexed: 11/09/2022]
Abstract
The frequencies of extended X-ray absorption fine-structure (EXAFS) measurements, which are oscillations occurring on the high-energy side of an X-ray absorption edge, can be used to identify interatomic distances in materials. We have used a dispersive X-ray spectrometer, which has no moving components, to make rapid measurements with minimal energy drift of the difference in EXAFS from the Fe K edge in an iron-cobalt thin film undergoing periodic strain through magnetostriction. We show that magnetostriction can be detected by differential X-ray absorption. The magnitude of the recorded signal relative to the noise shows a sensitivity to mean differential atomic motion of one femtometre: a factor of 100 times more sensitive than that normally available.
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17
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Duman E, Acet M, Wassermann EF, Itié JP, Baudelet F, Mathon O, Pascarelli S. Magnetic instabilities in Fe3C cementite particles observed with Fe K-edge x-ray circular dichroism under pressure. PHYSICAL REVIEW LETTERS 2005; 94:075502. [PMID: 15783825 DOI: 10.1103/physrevlett.94.075502] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2004] [Indexed: 05/24/2023]
Abstract
The ferromagnetic interstitial iron compound Fe(3)C (cementite) is expected to have Invar properties, whereby a high-moment to low-moment transition should occur when the atomic volume is reduced below a critical value. We, therefore, examine the pressure dependence of the Fe K-edge x-ray magnetic circular dichroism in Fe(3)C at ambient temperature and pressures up to 20 GPa. We find clear evidence for a high-moment to low-moment transition around 10 GPa.
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Affiliation(s)
- E Duman
- Experimentalphysik, Universität Duisburg-Essen, D-47048 Duisburg, Germany
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Mathon O, Baudelet F, Itié JP, Polian A, d'Astuto M, Chervin JC, Pascarelli S. Dynamics of the magnetic and structural alpha-epsilon phase transition in iron. PHYSICAL REVIEW LETTERS 2004; 93:255503. [PMID: 15697906 DOI: 10.1103/physrevlett.93.255503] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2004] [Indexed: 05/24/2023]
Abstract
We have studied the high-pressure iron bcc to hcp phase transition by simultaneous x-ray magnetic circular dichroism and x-ray absorption spectroscopy with an x-ray energy dispersive spectrometer. The combination of the two techniques allows us to obtain simultaneously information on both the structure and the magnetic state of iron under pressure. The magnetic and structural transitions simultaneously observed are sharp. Both are of first order in agreement with the theoretical prediction. The pressure domain of the transition observed (2.4+/-0.2 GPa) is narrower than that usually cited in the literature (8 GPa). Our data indicate that the magnetic transition slightly precedes the structural one, suggesting that the origin of the instability of the bcc phase in iron with increasing pressure is to be attributed to the effect of pressure on magnetism as predicted by spin-polarized full-potential total energy calculations.
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Affiliation(s)
- O Mathon
- European Synchrotron Radiation Facility, BP 220, 38043 Grenoble CEDEX, France
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