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Das S, Sumedha. Inverse transitions and disappearance of the λ-line in the asymmetric random-field Ising and Blume-Capel models. Phys Rev E 2023; 108:L042101. [PMID: 37978665 DOI: 10.1103/physreve.108.l042101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 10/06/2023] [Indexed: 11/19/2023]
Abstract
We report on reentrance in the random-field Ising and Blume-Capel models, induced by an asymmetric bimodal random-field distribution. The conventional continuous line of transitions between the paramagnetic and ferromagnetic phases, the λ-line, is wiped away by the asymmetry. The phase diagram, then, consists of only first-order transition lines that always end at ordered critical points. We find that, while for symmetric random-field distributions there is no reentrance, the asymmetry in the random-field results in a range of temperatures for which magnetization shows reentrance. While this does not give rise to an inverse transition in the Ising model, for the Blume-Capel model, however, there is a line of first-order inverse phase transitions that ends at an inverse-ordered critical point. We show that the location of the inverse transitions can be inferred from the ground-state phase diagram of the model.
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Affiliation(s)
- Santanu Das
- School of Physical Sciences, National Institute of Science Education and Research, Jatni 752050, India and Homi Bhabha National Institute, Training School Complex, Anushakti Nagar 400094, India
| | - Sumedha
- School of Physical Sciences, National Institute of Science Education and Research, Jatni 752050, India and Homi Bhabha National Institute, Training School Complex, Anushakti Nagar 400094, India
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Yahne DR, Pereira D, Jaubert LDC, Sanjeewa LD, Powell M, Kolis JW, Xu G, Enjalran M, Gingras MJP, Ross KA. Understanding Reentrance in Frustrated Magnets: The Case of the Er_{2}Sn_{2}O_{7} Pyrochlore. PHYSICAL REVIEW LETTERS 2021; 127:277206. [PMID: 35061439 DOI: 10.1103/physrevlett.127.277206] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 11/11/2021] [Indexed: 06/14/2023]
Abstract
Reentrance, the return of a system from an ordered phase to a previously encountered less-ordered one as a controlled parameter is continuously varied, is a recurring theme found in disparate physical systems, yet its microscopic cause is often not investigated thoroughly. Here, through detailed characterization and theoretical modeling, we uncover the microscopic mechanism behind reentrance in the strongly frustrated pyrochlore antiferromagnet Er_{2}Sn_{2}O_{7}. We use single crystal heat capacity measurements to expose that Er_{2}Sn_{2}O_{7} exhibits multiple instances of reentrance in its magnetic field B vs temperature T phase diagram for magnetic fields along three cubic high symmetry directions. Through classical Monte Carlo simulations, mean field theory, and classical linear spin-wave expansions, we argue that the origins of the multiple occurrences of reentrance observed in Er_{2}Sn_{2}O_{7} are linked to soft modes. These soft modes arise from phase competition and enhance thermal fluctuations that entropically stabilize a specific ordered phase, resulting in an increased transition temperature for certain field values and thus the reentrant behavior. Our work represents a detailed examination into the mechanisms responsible for reentrance in a frustrated magnet and may serve as a template for the interpretation of reentrant phenomena in other physical systems.
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Affiliation(s)
- D R Yahne
- Department of Physics, Colorado State University, 200 W. Lake Street, Fort Collins, Colorado 80523-1875, USA
| | - D Pereira
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - L D C Jaubert
- CNRS, Université de Bordeaux, LOMA, UMR 5798, 33400 Talence, France
| | - L D Sanjeewa
- Missouri Research Reactor, University of Missouri, Columbia, Missouri 65211, USA
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, USA
| | - M Powell
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634-0973, USA
| | - J W Kolis
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634-0973, USA
| | - Guangyong Xu
- NIST Center for Neutron Research, National Institutue of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - M Enjalran
- Department of Physics, Southern Connecticut State University, 501 Crescent Street, New Haven, Connecticut 06515-1355, USA
| | - M J P Gingras
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- CIFAR, MaRS Centre, West Tower 661 University Avenue, Suite 505, Toronto, Ontario M5G 1M1, Canada
| | - K A Ross
- Department of Physics, Colorado State University, 200 W. Lake Street, Fort Collins, Colorado 80523-1875, USA
- CIFAR, MaRS Centre, West Tower 661 University Avenue, Suite 505, Toronto, Ontario M5G 1M1, Canada
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