Electronic structure and spectroscopy of the quaternary Heusler alloy Co$_2$Cr$_{1-x}$Fe$_{x}$Al

TL;DR

This study combines experimental and theoretical methods to analyze the electronic structure and magnetic properties of the quaternary Heusler alloy Co$_2$Cr$_{1-x}$Fe$_{x}$Al, revealing how iron content influences magnetic moments and electronic states.

Contribution

It provides a comprehensive analysis of the electronic and magnetic properties of Co$_2$Cr$_{1-x}$Fe$_{x}$Al alloys using advanced spectroscopic and computational techniques, including element-specific magnetic moment determination.

Findings

Magnetic moments increase with higher iron content.

Element-specific magnetic moments were successfully measured.

Electronic density of states was characterized across different compositions.

Abstract

Quaternary Heusler alloys Co$_2$Cr$_{1-x}$Fe$_{x}$Al with varying Cr to Fe ratio $x$ were investigated experimentally and theoretically. The electronic structure and spectroscopic properties were calculated using the full relativistic Korringa-Kohn-Rostocker method with coherent potential approximation to account for the random distribution of Cr and Fe atoms as well as random disorder. Magnetic effects are included by the use of spin dependent potentials in the local spin density approximation. Magnetic circular dichroism in X-ray absorption was measured at the $L_{2,3}$ edges of Co, Fe, and Cr of the pure compounds and the $x=0.4$ alloy in order to determine element specific magnetic moments. Calculations and measurements show an increase of the magnetic moments with increasing iron content. Resonant (560eV - 800eV) soft X-ray as well as high resolution - high energy ($\geq 3.5$keV) hard X-ray photo emission was used to probe the density of the occupied states in Co$_2$Cr$_{0.6}$Fe$_{0.4}$Al.