Magnetocaloric and Magnetic Properties of Ni₂Mn_1-xCu_xGa Heusler Alloys: an Insight from the Direct Measurements and ab initio and Monte Carlo Calculations

Authors

V. Sokolovskiy
V. Buchelnikov
K. Skokov
O. Gutfleisch
D. Karpenkov
Yu Koshkid'ko
H. Miki
I. Dubenko
Naushad Ali, Southern Illinois University Carbondale
S. Stadler
V. Khovaylo

Comments

© 2013 American Institute of Physics

Published in Journal of Applied Physics, Vol. 114 No. 183913 (2013) at doi: 10.1063/1.4826366

Abstract

We calculated magnetic exchange constants and magnetocaloric properties of Ni₂Mn_1-xCu_xGa Heusler alloys by ab initio and Monte Carlo methods. The ab initio study of the influence of the Cu excess x on the strength of magnetic interactions revealed that Cu weakens Mn-Ni interaction and has a complex impact on the Mn-Mn interactions. Theoretically calculated magnetic phase diagram of Ni₂Mn_1-xCu_xGa is in a good agreement with available experimental data. Calculated by the Monte Carlo method the isothermal magnetic entropy change Delta S_mag in a Ni₂Mn_0.75Cu_0.25Ga alloy is significantly smaller around the coupled magnetostructural phase transition temperature than the reported earlier experimental Delta S_mag. This discrepancy is ascribed to an overestimation of the experimental Delta S_mag at the magnetostructural phase transition. Theoretically determined adiabatic temperature change Delta T_ad in Ni₂Mn_0.75Cu_0.25Ga agrees well with Delta T_ad measured experimentally by a direct method.

Recommended Citation

Sokolovskiy, V., Buchelnikov, V., Skokov, K., Gutfleisch, O., Karpenkov, D., Koshkid'ko, Yu, Miki, H., Dubenko, I., Ali, Naushad, Stadler, S. and Khovaylo, V.. "Magnetocaloric and Magnetic Properties of Ni₂Mn_1-xCu_xGa Heusler Alloys: an Insight from the Direct Measurements and ab initio and Monte Carlo Calculations." (Nov 2013).