scholarly journals Магнитострикционные аномалии редкоземельных фаз Лавеса c морфотропным фазовым переходом

2020 ◽  
Vol 62 (6) ◽  
pp. 839
Author(s):  
Г.А. Политова ◽  
М.А. Ганин ◽  
А.Б. Михайлова ◽  
А.В. Филимонов

Оver recent years in the process of searching for compounds with high or almost zero magnetostriction values, a number of pseudo-binary Laves RT2 phases with morphotropic phase transitions are attracted particular attention. That is, systems of compounds with a morphotropic phase boundary in the phase diagram. In this paper, the magnetic and magnetostrictive properties of multicomponent systems of compounds Tb0.2Dy0.8-хGdxCo2 and Tb0.2Dy0.8-хGdxCo1.9Al0.1 in which a morphotropic phase transition is observed when replacing dysprosium with gadolinium have been studied. A relationship between the temperature behavior, the sign and magnitude of magnetostrictive deformations, and the type of distortion of the cubic lattice of the studied Laves phases is revealed. In the region of magnetic phase transitions, the magnetocaloric effect was investigated.

2020 ◽  
Vol 514 ◽  
pp. 166988
Author(s):  
Baidyanath Sahu ◽  
Jia Yan Law ◽  
André M. Strydom ◽  
Victorino Franco ◽  
Harikrishnan S. Nair

2014 ◽  
Vol 215 ◽  
pp. 55-60 ◽  
Author(s):  
Sergey N. Martynov

A model for the description of two-subsystem Heisenberg ferrimagnet with frustrated intersubsystem exchange and competition between exchange interactions in a subsystem is proposed. The conditions of the existence of noncollinear Yafet-Kittel state and partially ordered magnetic structure are investigated. The phase diagram of competition parameter vs temperature is obtained in the mean field approximation. The peculiarities of the succesive magnetic phase transitions are considered.


2016 ◽  
Vol 45 (42) ◽  
pp. 16774-16778 ◽  
Author(s):  
Shota Yoneyama ◽  
Takeshi Kodama ◽  
Koichi Kikuchi ◽  
Takumi Fujisawa ◽  
Akira Yamaguchi ◽  
...  

Bis(glycolato)copper(ii) [Cu(HOCH2CO2)2] shows a large shift of the structural phase transition temperature by deuterium substitution of the hydroxyl groups in it.


An expression for the density of states of two electronic bands with intraand inter-band correlations has been derived. The consequences of the inter-band interaction on Mott-Hubbard split bands are discussed. The model is applied to explain the metal, semi-metal and magnetic phase transitions in NiS by using a semi-elliptical form for the density of states of non-interacting electrons. It is shown that the temperature-dependent overlap and hybridization parameters between d- and p-bands can provoke both the phase transitions in NiS as pointed out earlier by White & Mott (1971)


2004 ◽  
Vol 18 (15) ◽  
pp. 725-747 ◽  
Author(s):  
J. MIRA ◽  
J. RIVAS

We revise some recent results on the nature of the magnetic phase transition of ferromagnetic manganese perovskites with colossal magnetoresistance. It is found that they exhibit first-order magnetic phase transitions mainly due to strong lattice effects. The presence of such first-order transition is strongly linked to the existence of a temperature region above the Curie Temperature with a phase-separated regime of coexisting metallic and insulating clusters. This situation is compared with that of MnAs , paradigm of system with first-order magnetic phase transition, and we observe a parallel phenomenology of these apparently different systems. This serves as a clue for the finding of a phase-separated regime also in MnAs and, moreover, for the finding of a colossal magnetoresistive effect similar to that of manganese perovskites.


Author(s):  
L. T. Pawlicki ◽  
R. M. Siegoczyński ◽  
S. Ptasznik ◽  
K. Marszałek

AbstractThe main purpose of the experiment was a thermodynamic research with use of the electric methods chosen. The substance examined was olive oil. The paper presents the resistance, capacitive reactance, relative permittivity and resistivity of olive. Compression was applied with two mean velocities up to 450 MPa. The results were shown as functions of pressure and time and depicted on the impedance phase diagram. The three first order phase transitions have been detected. All the changes in material parameters were observed during phase transitions. The material parameters measured turned out to be the much more sensitive long-time phase transition factors than temperature. The values of material parameters and their dependence on pressure and time were compared with the molecular structure, arrangement of molecules and interactions between them. Knowledge about olive oil parameters change with pressure and its phase transitions is very important for olive oil production and conservation.


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