Magnetic States of the Ni1.75Co0.25Mn1.25Cr0.25In0.5 Heusler Alloy

The equilibrium magnetic and structural reference states of Co- and Cr-doped Ni₂Mn_1.5In_0.5 Heusler alloy are investigated by means of the first-principles method using a supercell approach. Three different ferrimagnetic and one ferromagnetic (FM) spin configurations, as well as two supercells with different distributions of excess Mn and In atoms, were considered. It is found that for supercell #1, the FM spin state in austenite is stable, where the martensite with different spin configurations is unstable, while in the case of supercell #2, a ferrimagnetic configuration for both austenite and martensite is favorable. The different trends for martensitic transformation were studied by c/a calculations for the tetragonal and orthorombic distortions of supercells along the z-axis and the y-axis, showing martensitic variants for supercell #2 at a ratio c/a > 1 and c/a <; 1$.