Improper ferromagnetic phase transitions in crystals

2005 ◽  
Vol 50 (5) ◽  
pp. 814-816
Author(s):  
S. V. Grigor’ev ◽  
B. M. Darinskii
Keyword(s):  
Phase Transitions ◽  
Ferromagnetic Phase

scholarly journals Imaging the formation and surface phase separation of the CE phase

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Haibiao Zhou ◽  
Qiyuan Feng ◽  
Yubin Hou ◽  
Masao Nakamura ◽  
Yoshinori Tokura ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Transitions ◽  
Charge Ordering ◽  
Zero Magnetic Field ◽  
Ferromagnetic Phase ◽  
Emergent Properties ◽  
Orbital Ordering ◽  
Strong Electron ◽  
Antiferromagnetic Correlation ◽  
Ordering Transitions

AbstractThe CE phase is an extraordinary phase exhibiting the simultaneous spin, charge, and orbital ordering due to strong electron correlation. It is an ideal platform to investigate the role of the multiple orderings in the phase transitions and discover emergent properties. Here, we use a cryogenic high-field magnetic force microscope to image the phase transitions and properties of the CE phase in a Pr0.5Ca0.5MnO3 thin film. In a high magnetic field, we observed a clear suppression of magnetic susceptibility at the charge-ordering insulator transition temperature (TCOI), whereas, at the Néel temperature (TN), no significant change is observed. This observation favors the scenario of strong antiferromagnetic correlation developed below TCOI but raises questions about the Zener polaron paramagnetic phase picture. Besides, we discoverd a phase-separated surface state in the CE phase regime. Ferromagnetic phase domains residing at the surface already exist in zero magnetic field and show ultra-high magnetic anisotropy. Our results provide microscopic insights into the unconventional spin- and charge-ordering transitions and revealed essential attributes of the CE phase, highlighting unusual behaviors when multiple electronic orderings are involved.

Mössbauer study of ferromagnetic phase transitions in(Pd1−xAgx)0.99Fe0.01alloys

1974 ◽  
Vol 9 (3) ◽  
pp. 1085-1091 ◽  
Author(s):  
R. A. Levy ◽  
J. J. Burton ◽  
D. I. Paul ◽  
J. I. Budnick
Keyword(s):  
Phase Transitions ◽  
Ferromagnetic Phase ◽  
Mössbauer Study

Hysteresis loops for para–ferromagnetic phase transitions

2011 ◽  
Vol 62 (6) ◽  
pp. 1013-1026 ◽  
Author(s):  
M. Fabrizio ◽  
G. Matarazzo ◽  
M. Pecoraro
Keyword(s):  
Phase Transitions ◽  
Hysteresis Loops ◽  
Ferromagnetic Phase

scholarly journals Bootstrapping mixed correlators in three-dimensional cubic theories

2019 ◽  
Vol 6 (3) ◽  
Author(s):  
Stefanos R. Kousvos ◽  
Andreas Stergiou
Keyword(s):  
Phase Transitions ◽  
Parameter Space ◽  
Structural Phase ◽  
Three Dimensional ◽  
Ferromagnetic Phase ◽  
Structural Phase Transitions ◽  
Cubic Symmetry ◽  
Conformal Field ◽  
Conformal Bootstrap ◽  
Crossing Symmetry

Three-dimensional theories with cubic symmetry are studied using the machinery of the numerical conformal bootstrap. Crossing symmetry and unitarity are imposed on a set of mixed correlators, and various aspects of the parameter space are probed for consistency. An isolated allowed region in parameter space is found under certain assumptions involving pushing operator dimensions above marginality, indicating the existence of a conformal field theory in this region. The obtained results have possible applications for ferromagnetic phase transitions as well as structural phase transitions in crystals. They are in tension with previous \epsilonϵ expansion results, as noticed already in earlier work.

scholarly journals Subpicosecond metamagnetic phase transition driven by non-equilibrium electron dynamics

2021 ◽  
Author(s):  
Federico Pressacco ◽  
Davide Sangalli ◽  
Vojtěch Uhlíř ◽  
Dmytro Kutnyakhov ◽  
Jon Ander Arregi ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Ab Initio ◽  
Photoelectron Spectroscopy ◽  
Electronic Band Structure ◽  
Ferromagnetic Phase ◽  
Electron Dynamics ◽  
Electronic Band ◽  
Time Resolved ◽  
Non Equilibrium

Abstract Femtosecond light-induced phase transitions between different macroscopic orders provide the possibility to tune the functional properties of condensed matter on ultrafast timescales. In first-order phase transitions, transient non-equilibrium phases and inherent phase coexistence often preclude non-ambiguous detection of transition precursors and their temporal onset. Here, we present a study combining time-resolved photoelectron spectroscopy and ab-initio electron dynamics calculations elucidating the transient subpicosecond processes governing the photoinduced generation of ferromagnetic order in antiferromagnetic FeRh. The transient photoemission spectra are accounted for by assuming that not only the occupation of electronic states is modified during the photoexcitation process. Instead, the photo-generated non-thermal distribution of electrons modifies the electronic band structure. The ferromagnetic phase of FeRh, characterized by a minority band near the Fermi energy, is established 350 ± 30 fs after the laser excitation. Ab-initio calculations indicate that the phase transition is initiated by a photoinduced Rh-to-Fe charge transfer.

scholarly journals Non-equilibrium Phase Transitions in 2D Small-World Networks: Competing Dynamics

Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Wei Liu ◽  
Zhengxin Yan ◽  
Gaoliang Zhou
Keyword(s):  
Phase Transitions ◽  
Tricritical Point ◽  
Equilibrium Phase ◽  
Finite Size ◽  
Small World ◽  
Ferromagnetic Phase ◽  
Kawasaki Dynamics ◽  
Small World Networks ◽  
Competing Dynamics ◽  
Non Equilibrium

Abstract This article offers a detailed analysis of the Ising model in 2D small-world networks with competing Glauber and Kawasaki dynamics. The non-equilibrium stationary state phase transitions are obtained in these networks. The phase transitions are discussed, and the phase diagrams are obtained via Monte Carlo simulations and finite-size analyzing. We find that as the addition of links increases the phase transition temperature increases and the transition competing probability of tricritical point decreases. For the competition of the two dynamics, ferromagnetic to anti-ferromagnetic phase transitions and the critical endpoints are found in the small-world networks.

Exact determination of hysteresis and phase transition temperature of ferromagnetic materials using an N-soliton wave statistics

2014 ◽  
Vol 28 (18) ◽  
pp. 1450148 ◽  
Author(s):  
Babur M. Mirza
Keyword(s):  
Wave Function ◽  
Statistical Theory ◽  
Phase Transitions ◽  
Ferromagnetic Materials ◽  
Wave Functions ◽  
Ferromagnetic Phase ◽  
Linear Superposition ◽  
Wave Statistics ◽  
Exact Determination

In this paper, a statistical theory of N-soliton systems with antisymmetric wave functions is presented. As such, the wave functions of the soliton waves have equal but opposite amplitudes. In the wave function representation, the governing energy and continuity conditions are found to be linear, admitting a linear superposition of the soliton waves functions. This property is used to form the combined wave function for the system hence to calculate its total (macroscopic) energy. The statistical theory is applied to model phase transitions in ferromagnetic materials, and used for the case of common ferromagnetic substances, such as iron (26 Fe ), cobalt (27 Co ) and nickel (28 Ni ). The estimated first phase transitions are found to correspond to the respective Curie temperatures of these substances. Based on the energy calculations, the general hysteresis behavior of ferromagnetic materials is derived as a consequence of the model. The statistical theory is useful in the study of ferromagnetic phase transitions, for estimating the Curie point temperature, and an exact determination of the heat capacity of magnetic materials.

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