1
|
Vergara LI, Cao J, Rogado N, Wang YQ, Chaudhury RP, Cava RJ, Lorenz B, Musfeldt JL. Magnetoelastic coupling in multiferroic Ni3V2O8. Phys Rev B 2009; 80:052303. [DOI: 10.1103/physrevb.80.052303] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
|
2
|
Cabrera I, Kenzelmann M, Lawes G, Chen Y, Chen WC, Erwin R, Gentile TR, Leão JB, Lynn JW, Rogado N, Cava RJ, Broholm C. Coupled magnetic and ferroelectric domains in multiferroic Ni3V2O8. Phys Rev Lett 2009; 103:087201. [PMID: 19792753 DOI: 10.1103/physrevlett.103.087201] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Indexed: 05/28/2023]
Abstract
Electric control of multiferroic domains is demonstrated through polarized magnetic neutron diffraction. Cooling to the cycloidal multiferroic phase of Ni3V2O8 in an electric field E causes the incommensurate Bragg reflections to become neutron spin polarizing, the sense of neutron polarization reversing with E. Quantitative analysis indicates the E-treated sample has a handedness that can be reversed by E. We further show a close association between cycloidal and ferroelectric domains through E-driven spin and electric polarization hysteresis. We suggest that a definite cycloidal handedness is achieved through magnetoelastically induced Dzyaloshinskii-Moriya interactions.
Collapse
Affiliation(s)
- I Cabrera
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
3
|
|
4
|
Yildirim T, Vergara LI, Íñiguez J, Musfeldt JL, Harris AB, Rogado N, Cava RJ, Yen F, Chaudhury RP, Lorenz B. Phonons and magnetoelectric interactions in Ni 3V 2O 8. J Phys : Condens Matter 2008; 20:434214. [DOI: 10.1088/0953-8984/20/43/434214] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
|
5
|
Lawes G, Harris AB, Kimura T, Rogado N, Cava RJ, Aharony A, Entin-Wohlman O, Yildirim T, Kenzelmann M, Broholm C, Ramirez AP. Magnetically driven ferroelectric order in Ni3V2O8. Phys Rev Lett 2005; 95:087205. [PMID: 16196898 DOI: 10.1103/physrevlett.95.087205] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2005] [Indexed: 05/04/2023]
Abstract
We show that long-range ferroelectric and incommensurate magnetic order appear simultaneously in a single phase transition in Ni3V2O8. The temperature and magnetic-field dependence of the spontaneous polarization show a strong coupling between magnetic and ferroelectric orders. We determine the magnetic symmetry using Landau theory for continuous phase transitions, which shows that the spin structure alone can break spatial inversion symmetry leading to ferroelectric order. This phenomenological theory explains our experimental observation that the spontaneous polarization is restricted to lie along the crystal b axis and predicts that the magnitude should be proportional to a magnetic order parameter.
Collapse
Affiliation(s)
- G Lawes
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Lawes G, Kenzelmann M, Rogado N, Kim KH, Jorge GA, Cava RJ, Aharony A, Entin-Wohlman O, Harris AB, Yildirim T, Huang QZ, Park S, Broholm C, Ramirez AP. Competing magnetic phases on a kagomé staircase. Phys Rev Lett 2004; 93:247201. [PMID: 15697855 DOI: 10.1103/physrevlett.93.247201] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2004] [Indexed: 05/24/2023]
Abstract
We present thermodynamic and neutron data on Ni3V2O8, a spin-1 system on a kagomé staircase. The extreme degeneracy of the kagomé antiferromagnet is lifted to produce two incommensurate phases at finite T--one amplitude modulated, the other helical--plus a commensurate canted antiferromagnet for T-->0. The H-T phase diagram is described by a model of competing first and second neighbor interactions with smaller anisotropic terms. Ni3V2O8 thus provides an elegant example of order from subleading interactions in a highly frustrated system.
Collapse
Affiliation(s)
- G Lawes
- Los Alamos National Laboratory, Los Alamos, NM 87544, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Heinrich M, Krug von Nidda HA, Loidl A, Rogado N, Cava RJ. Potential signature of a Kosterlitz-Thouless transition in BaNi2V2O8. Phys Rev Lett 2003; 91:137601. [PMID: 14525336 DOI: 10.1103/physrevlett.91.137601] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2003] [Revised: 07/08/2003] [Indexed: 05/24/2023]
Abstract
ESR measurements are reported for the quasi-two-dimensional honeycomb antiferromagnet BaNi2V2O8. Planar anisotropic properties are confirmed by angular dependent investigations of resonance field and linewidth. The divergence of the temperature-dependent linewidth on approaching T(N) from above is described in terms of the Kosterlitz-Thouless transition, the critical behavior close to long-range magnetic order, and the 2D Heisenberg antiferromagnet. We provide arguments that the Kosterlitz-Thouless scenario is compatible with the observed critical exponent and suggest BaNi2V2O8 is a weakly anisotropic 2D Heisenberg antiferromagnet.
Collapse
Affiliation(s)
- M Heinrich
- Experimentalphysik V, Elektronische Korrelationen und Magnetismus, Institut für Physik, Universität Augsburg, D-86135 Augsburg, Germany
| | | | | | | | | |
Collapse
|
8
|
Yildirim T, Gülseren O, Lynn JW, Brown CM, Udovic TJ, Huang Q, Rogado N, Regan KA, Hayward MA, Slusky JS, He T, Haas MK, Khalifah P, Inumaru K, Cava RJ. Giant anharmonicity and nonlinear electron-phonon coupling in MgB2: a combined first-principles calculation and neutron scattering study. Phys Rev Lett 2001; 87:037001. [PMID: 11461581 DOI: 10.1103/physrevlett.87.037001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2001] [Indexed: 05/23/2023]
Abstract
First-principles calculations of the electronic band structure and lattice dynamics for the new superconductor MgB (2) are carried out and found to be in excellent agreement with our inelastic neutron scattering measurements. The numerical results reveal that the E(2g) in-plane boron phonons near the zone center are very anharmonic and strongly coupled to the planar B sigma bands near the Fermi level. This giant anharmonicity and nonlinear electron-phonon coupling is key to quantitatively explaining the observed high T(c) and boron isotope effect in MgB (2).
Collapse
Affiliation(s)
- T Yildirim
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Eom CB, Lee MK, Choi JH, Belenky LJ, Song X, Cooley LD, Naus MT, Patnaik S, Jiang J, Rikel M, Polyanskii A, Gurevich A, Cai XY, Bu SD, Babcock SE, Hellstrom EE, Larbalestier DC, Rogado N, Regan KA, Hayward MA, He T, Slusky JS, Inumaru K, Haas MK, Cava RJ. High critical current density and enhanced irreversibility field in superconducting MgB2 thin films. Nature 2001; 411:558-60. [PMID: 11385563 DOI: 10.1038/35079018] [Citation(s) in RCA: 442] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The discovery of superconductivity at 39 K in magnesium diboride offers the possibility of a new class of low-cost, high-performance superconducting materials for magnets and electronic applications. This compound has twice the transition temperature of Nb3Sn and four times that of Nb-Ti alloy, and the vital prerequisite of strongly linked current flow has already been demonstrated. One possible drawback, however, is that the magnetic field at which superconductivity is destroyed is modest. Furthermore, the field which limits the range of practical applications-the irreversibility field H*(T)-is approximately 7 T at liquid helium temperature (4.2 K), significantly lower than about 10 T for Nb-Ti (ref. 6) and approximately 20 T for Nb3Sn (ref. 7). Here we show that MgB2 thin films that are alloyed with oxygen can exhibit a much steeper temperature dependence of H*(T) than is observed in bulk materials, yielding an H* value at 4.2 K greater than 14 T. In addition, very high critical current densities at 4.2 K are achieved: 1 MA cm-2 at 1 T and 105 A cm-2 at 10 T. These results demonstrate that MgB2 has potential for high-field superconducting applications.
Collapse
Affiliation(s)
- C B Eom
- Department of Materials Science and Engineering, University of Wisconsin, Madison, Wisconsin 53706, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
He T, Huang Q, Ramirez AP, Wang Y, Regan KA, Rogado N, Hayward MA, Haas MK, Slusky JS, Inumara K, Zandbergen HW, Ong NP, Cava RJ. Superconductivity in the non-oxide perovskite MgCNi3. Nature 2001; 411:54-6. [PMID: 11333973 DOI: 10.1038/35075014] [Citation(s) in RCA: 530] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The interplay of magnetic interactions, the dimensionality of the crystal structure and electronic correlations in producing superconductivity is one of the dominant themes in the study of the electronic properties of complex materials. Although magnetic interactions and two-dimensional structures were long thought to be detrimental to the formation of a superconducting state, they are actually common features of both the high transition-temperature (Tc) copper oxides and low-Tc material Sr2RuO4, where they appear to be essential contributors to the exotic electronic states of these materials. Here we report that the perovskite-structured compound MgCNi3 is superconducting with a critical temperature of 8 K. This material is the three-dimensional analogue of the LnNi2B2C family of superconductors, which have critical temperatures up to 16 K (ref. 2). The itinerant electrons in both families of materials arise from the partial filling of the nickel d-states, which generally leads to ferromagnetism as is the case in metallic Ni. The high relative proportion of Ni in MgCNi3 suggests that magnetic interactions are important, and the lower Tc of this three-dimensional compound-when compared to the LnNi2B2C family-contrasts with conventional ideas regarding the origins of superconductivity.
Collapse
Affiliation(s)
- T He
- Department of Chemistry and Princeton Materials Institute, Princeton, New Jersey, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Monteverde M, Núñez-Regueiro M, Rogado N, Regan KA, Hayward MA, He T, Loureiro SM, Cava RJ. Pressure dependence of the superconducting transition temperature of magnesium diboride. Science 2001; 292:75-7. [PMID: 11283353 DOI: 10.1126/science.1059775] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We studied the pressure and temperature dependence of the electrical resistivity of the superconducting compound magnesium diboride (MgB(2)). The superconducting transition temperature decreases monotonically with pressure, being parabolic or linear, depending on samples. The rate of decrease under pressure is higher than in conventional superconductors. We discuss our results in terms of the semimetallic character of the electronic band structure of MgB(2).
Collapse
Affiliation(s)
- M Monteverde
- Centre de Recherches sur les Très Basses Températures, CNRS, BP166 Cedex 09, 38042 Grenoble, France
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Slusky JS, Rogado N, Regan KA, Hayward MA, Khalifah P, He T, Inumaru K, Loureiro SM, Haas MK, Zandbergen HW, Cava RJ. Loss of superconductivity with the addition of Al to MgB2 and a structural transition in Mg1-x AlxB2. Nature 2001; 410:343-5. [PMID: 11268204 DOI: 10.1038/35066528] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The basic magnetic and electronic properties of most binary compounds have been well known for decades. The recent discovery of superconductivity at 39 K in the simple binary ceramic compound magnesium diboride, MgB2, was therefore surprising. Indeed, this material has been known and structurally characterized since the mid 1950s (ref. 2), and is readily available from chemical suppliers (it is commonly used as a starting material for chemical metathesis reactions). Here we show that the addition of electrons to MgB2, through partial substitution of Al for Mg, results in the loss of superconductivity. Associated with the Al substitution is a subtle but distinct structural transition, reflected in the partial collapse of the spacing between boron layers near an Al content of 10 per cent. This indicates that superconducting MgB2 is poised very near a structural instability at slightly higher electron concentrations.
Collapse
Affiliation(s)
- J S Slusky
- Department of Chemistry and Princeton Materials Institute, Princeton University, New Jersey 08544, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Larbalestier DC, Cooley LD, Rikel MO, Polyanskii AA, Jiang J, Patnaik S, Cai XY, Feldmann DM, Gurevich A, Squitieri AA, Naus MT, Eom CB, Hellstrom EE, Cava RJ, Regan KA, Rogado N, Hayward MA, He T, Slusky JS, Khalifah P, Inumaru K, Haas M. Strongly linked current flow in polycrystalline forms of the superconductor MgB2. Nature 2001; 410:186-9. [PMID: 11242073 DOI: 10.1038/35065559] [Citation(s) in RCA: 820] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The discovery of superconductivity at 39 K in magnesium diboride, MgB2, raises many issues, a critical one being whether this material resembles a high-temperature copper oxide superconductor or a low-temperature metallic superconductor in terms of its behaviour in strong magnetic fields. Although the copper oxides exhibit very high transition temperatures, their in-field performance is compromized by their large anisotropy, the result of which is to restrict high bulk current densities to a region much less than the full magnetic-field-temperature (H-T) space over which superconductivity is found. Moreover, the weak coupling across grain boundaries makes transport current densities in untextured polycrystalline samples low and strongly sensitive to magnetic field. Here we report that, despite the multiphase, untextured, microscale, subdivided nature of our MgB2 samples, supercurrents flow throughout the material without exhibiting strong sensitivity to weak magnetic fields. Our combined magnetization, magneto-optical, microscopy and X-ray investigations show that the supercurrent density is mostly determined by flux pinning, rather than by the grain boundary connectivity. Our results therefore suggest that this new superconductor class is not compromized by weak-link problems, a conclusion of significance for practical applications if higher temperature analogues of this compound can be discovered.
Collapse
Affiliation(s)
- D C Larbalestier
- Applied Superconductivity Center, University of Wisconsin-Madison, 1500 Engineering Drive, Madison, Wisconsin 53706, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|