Magnetocaloric and magnetic properties of Ni2Mn1-xCuxGa Heusler alloys: An insight from the direct measurements and ab initio and Monte Carlo calculations

作者：Sokolovskiy V^*; Buchelnikov V; Skokov K; Gutfleisch O; Karpenkov D; Koshkid' ko Yu; Miki H; Dubenko I; Ali N; Stadler S; Khovaylo V

来源：Journal of Applied Physics, 2013, 114(18): 183913.

DOI：10.1063/1.4826366

We calculated magnetic exchange constants and magnetocaloric properties of Ni2Mn1-xCuxGa 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 Ni2Mn1-xCuxGa 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 Ni2Mn0.75Cu0.25Ga 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 Ni2Mn0.75Cu0.25Ga agrees well with Delta T-ad measured experimentally by a direct method.

• 出版日期2013-11-14