Itinerant and local magnetic moments in ferrimagnetic Mn2CoGa thin films probed by x-ray magnetic linear dichroism: experiment and ab initio theory

TL;DR

This study combines experimental x-ray magnetic linear dichroism measurements with ab initio DFT calculations to investigate the nature of magnetic moments in Mn2CoGa thin films, revealing coexistence of itinerant and local Mn moments.

Contribution

It provides a detailed experimental and theoretical analysis of magnetic moments in Mn2CoGa thin films, distinguishing local and itinerant character using x-ray dichroism and non-collinear DFT.

Findings

Identification of antiparallel Mn moments via XMCD

Distinction between local and itinerant Mn moments using XMLD

Agreement between experimental spectra and DFT calculations

Abstract

Epitaxial thin films of the half-metallic Xa-compound Mn2CoGa (Hg2CuTi prototype) were prepared by dc magnetron co-sputtering with different heat treatments on MgO (001) substrates. High-quality films with a bulk magnetization of 1.95(5)\mu_B per unit cell were obtained. The L3,2 x-ray magnetic circular dichroism spectra agree with calculations based on density functional theory (DFT) and reveal the antiparallel alignment of the two inequivalent Mn moments. X-ray magnetic linear dichroism, in good agreement with theory as well, allows to distinguish between itinerant and local Mn moments. Based on non-collinear spin DFT it is shown that one of the two Mn moments has local character, whereas the other Mn moment and the Co moment are itinerant.