Phase Diagrams of Ni2MnX (X = In, Sn, Sb) Heusler Alloys with Inversion of Exchange Interaction

In this work with the help of the phenomenological Ginzburg-Landau theory of structural and magnetic phase transitions the phase diagrams of Heusler Ni-Mn-X (X = In, Sn, Sb) alloys with the inversion of exchange interaction are investigated. The investigation shows that the type of the phase diagrams in Heusler Ni-Mn-X (X = In, Sn, Sb) alloys depends on the value and sign of the free energy parameters. As it is seen from the analysis of the phase diagrams with the determined values and signs of the parameters of Landau functional there are thermodynamic paths which allow to explain experimental phase transitions in Heusler alloys Ni-Mn-X (X = In, Sn, Sb) and Ni-Co- Mn-X (X = In, Sn, Sb) qualitatively.

Download Full-text

Concentration Phase Transitions in Two-Sublattice Magnets

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.557-559.731 ◽

2012 ◽

Vol 557-559 ◽

pp. 731-734 ◽

Cited By ~ 3

Author(s):

Valery I. Belokon ◽

Konstantin V. Nefedev ◽

Olga I. Dyachenko

Keyword(s):

Phase Transitions ◽

Exchange Interaction ◽

Critical Phenomena ◽

Random Fields ◽

Magnetic Phase ◽

Critical Concentration ◽

Magnetic Phase Transitions ◽

System Of Equations ◽

Sublattice Model ◽

Interaction Method

Phase transitions and critical phenomena are investigated within a two-sublattice model. In the framework of the random fields with the exchange interaction method the system of equations is obtained. It allows us to establish conditions under which magnetic phase transitions are possible. Critical concentration of ferromagnetic atoms which is necessary for the existence of ferromagnetic, ferrimagnetic and antiferromagnetic phases is determined.

Download Full-text

Phase diagrams of Ni2+xMn1-xGa Heusler alloys from Hubbard Hamiltonian with account of Jahn-Teller effect

MRS Proceedings ◽

10.1557/opl.2011.633 ◽

2011 ◽

Vol 1310 ◽

Author(s):

Mikhail A. Zagrebin ◽

Vasiliy D. Buchelnikov ◽

Sergey V. Taskaev ◽

Natal’ya Yu. Fedulova

Keyword(s):

Phase Diagram ◽

Free Energy ◽

Phase Transitions ◽

Phase Diagrams ◽

Density Of States ◽

Heusler Alloys ◽

Teller Effect ◽

Hubbard Hamiltonian ◽

Jahn Teller ◽

Jahn Teller Effect

ABSTRACTIn this work a microscopic Hamiltonian is investigated using the Hubbard model for a ferromagnet with two degenerate bands, taking into account the Jahn-Teller effect. A macroscopic free energy is obtained from the microscopic Hubbard Hamiltonian. All free energy coefficients depend on microscopic parameters: temperature T and composition x. As a result of analytical minimization of free energy, phase diagrams are numerically constructed. It is shown that at certain values of parameters on the phase diagrams there are thermodynamic paths which correspond to experimentally observed sequences of phase transitions. Using density of states spectra for different compositions x the T-x phase diagram is numerically constructed. This phase diagram can theoretically explain experimentally observed behavior of the temperatures of phase transitions.

Download Full-text

Field-induced magnetic phase transitions in ferrimagnet GdMn2Ge2: H - T magnetic phase diagrams

Journal of Central South University of Technology ◽

10.1007/s11771-000-0044-6 ◽

2000 ◽

Vol 7 (2) ◽

pp. 107-110

Author(s):

Guang-hua Guo ◽

R. Z. Levitin ◽

N. P. Kolmakova

Keyword(s):

Phase Transitions ◽

Phase Diagrams ◽

Magnetic Phase ◽

Magnetic Phase Transitions ◽

Magnetic Phase Diagrams

Download Full-text

Magnetic phase transitions and phase diagrams of DyMn2Ge2

Journal of Experimental and Theoretical Physics ◽

10.1134/1.1420448 ◽

2001 ◽

Vol 93 (4) ◽

pp. 796-804 ◽

Cited By ~ 5

Author(s):

Guo Guanghua ◽

M. V. Eremin ◽

A. Kirste ◽

N. P. Kolmakova ◽

A. S. Lagutin ◽

...

Keyword(s):

Phase Transitions ◽

Phase Diagrams ◽

Magnetic Phase ◽

Magnetic Phase Transitions

Download Full-text

Magnetic Phase Transitions in La1-xRxMn2Si2 (R=Gd, Tb, Dy) Compounds

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.190.171 ◽

2012 ◽

Vol 190 ◽

pp. 171-174 ◽

Cited By ~ 1

Author(s):

E.G. Gerasimov ◽

N.V. Mushnikov ◽

V.S. Gaviko

Keyword(s):

Phase Transitions ◽

Phase Diagrams ◽

Magnetic Measurements ◽

Magnetic Phase ◽

Magnetic Phase Transitions ◽

Magnetic Structures ◽

Easy Direction ◽

Irreversible Magnetization ◽

Magnetization Processes ◽

Magnetic Phase Diagrams

Magnetic properties of the La1xRxMn2Si2 (R is Gd, Tb, Dy; 0 x 1) compounds were investigated using magnetic measurements on quasi-single crystals. The x-T concentration magnetic phase diagrams are constructed. All obtained x-T magnetic phase diagrams are found to be similar. Six magnetic structures are realized in the compounds at different concentrations x. It was shown that all the compounds have strong magnetic anisotropy with the c-axis as the easy direction. For the compounds with x = 0.2, the irreversible magnetization processes are observed which can be attributed to the existence of a compensation point at which the R and Mn magnetic sublattices compensate each other. The nature of various spontaneous and field-induced phase transitions is also discussed.

Download Full-text

Influence of the f-d exchange interaction on the field-induced magnetic phase transitions in the Y1−tGdtCo3 intermetallics

Physica B Condensed Matter ◽

10.1016/0921-4526(94)00950-z ◽

1995 ◽

Vol 211 (1-4) ◽

pp. 87-89 ◽

Cited By ~ 2

Author(s):

H. Aruga Katori ◽

I.S. Dubenko ◽

I.Yu. Gaidukova ◽

T. Goto ◽

R.Z. Levitin ◽

...

Keyword(s):

Phase Transitions ◽

Exchange Interaction ◽

Magnetic Phase ◽

Magnetic Phase Transitions

Download Full-text

Effect of the Interatomic Exchange Interaction on the Magnetic Phase Transitions in Spin Crossover Systems under High-Pressure

Physics of the Solid State ◽

10.1134/s1063783418060276 ◽

2018 ◽

Vol 60 (6) ◽

pp. 1177-1179 ◽

Cited By ~ 1

Author(s):

S. G. Ovchinnikov ◽

Yu. S. Orlov ◽

S. V. Nikolaev ◽

A. I. Nesterov ◽

T. M. Ovchinnikova

Keyword(s):

High Pressure ◽

Phase Transitions ◽

Exchange Interaction ◽

Spin Crossover ◽

Magnetic Phase ◽

Magnetic Phase Transitions

Download Full-text

Phase Diagrams for Incommensurate Systems

MRS Proceedings ◽

10.1557/proc-21-75 ◽

1982 ◽

Vol 21 ◽

Author(s):

P. Toledano

Keyword(s):

Free Energy ◽

Phase Transitions ◽

Energy Density ◽

Phase Diagrams ◽

Order Parameter ◽

Landau Theory ◽

Free Energy Density ◽

Lock In

ABSTRACTPhase diagrams, for systems undergoing one or several incommensurate and lock-in transitions, are discussed in the framework of the Landau theory of phase transitions. It is shown that their essential features can be deduced from the explicit forms of the free-energy density ø and the k-dispersion of the coefficient α(→k)of the quadratic contribution of the order-parameter components in ø. Two families of phase diagrams are distinguished depending on symmetry considerations.

Download Full-text

Monte Carlo Study of Magnetostructural Phase Transitions in Ni50Mn25+xSb25-x Heusler Alloys

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.154.139 ◽

2009 ◽

Vol 154 ◽

pp. 139-144 ◽

Cited By ~ 1

Author(s):

V.V. Sokolovskiy ◽

Vasiliy D. Buchelnikov ◽

Sergey Taskaev

Keyword(s):

Monte Carlo ◽

Phase Transitions ◽

Monte Carlo Simulations ◽

Magnetic Phase ◽

Heusler Alloys ◽

Monte Carlo Study ◽

Magnetic Phase Transitions ◽

Antiferromagnetic Exchange ◽

Magnetization Curves ◽

Model Hamiltonian

On the basis of Monte Carlo simulations, we investigate the temperature dependence of magnetization of Ni-Mn-Sb Heusler alloys, in which the part of the Mn atoms interact antiferromagnetically. It is shown that this antiferromagnetic exchange is responsible for existence of several magnetic phase transitions in the Heusler alloys. For a certain set of parameters of the model Hamiltonian we obtain coupled martensitic and magnetic phase transitions. Results of simulations agree in an excellent way with the experimental magnetization curves.

Download Full-text