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Monte Carlo Simulations of Thermal Hysteresis in Ni‐Mn‐Based Heusler Alloys
Author(s) -
Sokolovskiy Vladimir,
Zagrebin Mikhail,
Buchelnikov Vasiliy,
Entel Peter
Publication year - 2018
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201700265
Subject(s) - condensed matter physics , monte carlo method , austenite , materials science , hysteresis , ising model , martensite , magnetization , thermal expansion , phase diagram , hamiltonian (control theory) , thermodynamics , phase (matter) , physics , magnetic field , microstructure , metallurgy , quantum mechanics , mathematics , statistics , mathematical optimization
We present a study of the thermal hysteresis that takes place across the magnetostructural phase transition of the Ni‐Mn‐based Heusler alloys. The results have been obtained by means of first‐principles calculations and Monte Carlo simulations based on the proposed Potts‐Blume‐Emery‐Griffiths Hamiltonian involving magnetic and elastic degrees of freedom. First, separating the structural and magnetic contributions, we calculate the phase diagram including the martensitic transformation as a function of ratio between exchange structural constants in martensite and austenite ( K / J ). It is shown that the width of the thermal hysteresis depends on K / J and it is found to increase at a ratio of K / J between 0.20 and 0.37. A similar trend is also observed for the Landau free energy expansion. The evolutions of the magnetization and deformation order parameter of alloys studied under various applied magnetic fields are simulated as functions of temperature upon heating and cooling cycles. Furthermore, under high applied fields the nonlinear shift ofd T m / d H e x tand change of hysteresis width according to the relation between magnetostructural interaction constants ( U 1andU 2 ) are observed. The results obtained with the Monte Carlo routine are discussed and demonstrated a good agreement with experimental data.