Volume dependence of magnetic properties in Co2Cr1-xYxGa (Y=Ti-Ni) Heusler alloys: a first-principles study

TL;DR

This study uses first-principles calculations to explore how volume changes affect magnetic properties in Co2Cr1-xYxGa Heusler alloys, revealing wide tunability in magnetic moments and Curie temperatures.

Contribution

It provides a comprehensive first-principles analysis of volume-dependent magnetic properties across a broad compositional range of quaternary Heusler alloys.

Findings

Magnetic moments vary from 0.8 to 4.9 μ_B.

Curie temperatures range from 130 K to 1250 K.

Pressure derivatives of TC range from -7 to +6.3 K/ų.

Abstract

The magnetic properties tuning and volume dependence in the series of quaternary full Heusler alloys with formula Co2Cr1-xYGa (Y = Ti, V, Mn, Fe, Co, Ni) were studied with a detailed first-principles exploration. We employ the density functional KKR method with the coherent potential approximation, estimating effective Heisenberg exchange constants via the magnetic force theorem together with mean-field Curie temperature (TC) and magnetic moment for compositions in the whole concentration range. The volumetric dependency of these magnetic properties is studied, particularly the pressure derivatives of TC at equilibrium. Our ternary alloy calculations show good agreement with local-density and generalized gradient approximations in the literature. The quaternary alloys show a wide range of tunable magnetic properties, where magnetic moments range from 0.8 to 4.9 mu_B, TC from 130 K to 1250 K, and dTC/dV values range from -7 to +6.3 K A-3.