Investigation of Magnetic Entropy Change and Critical Behavior Analysis of Cu- and Si-Doped Ni–Mn–Sn Heusler Alloys

Abstract

We have studied the magnetic property as a function of temperature and magnetic field (μ0.H) and critical exponent on Ni–Mn-based Heusler alloys such as Ni46Mn41Sn13 (NMS), Ni46Mn41Sn10Si3 (NMSS), and Ni46Mn38Cu3Sn13 (NMCS). Magneto entropy change and the order of phase transition are estimated around the martensite and austenite phases of all these samples. Magnetic critical behavior of each sample is analyzed around second-order ferromagnetic (FM) austenite phase transition employing Arrott and Kouvel–Fisher plots. The reliability of estimated critical exponents is verified by Widom scaling relation and M3 vs H plot. Furthermore, one more local exponent n which depends on the magnetic state is also estimated through the isothermal magnetization of magnetic entropy change (∆SM) plots of all these samples. The obtained values for all these alloys are well close to the mean-field theoretical model and it is proposed that the existence of long-range magnetic interaction around austenite transition of these materials.