Magnetic and Electronic Properties of Weyl Semimetal Co2MnGa Thin Films.

Peter Swekis,Gerhard H Fecher,Dmytro S Inosov,Yi-Cheng Chen,Andrei Gloskovskii,Claudia Felser,Sebastian T B Goennenwein,Anastasios Markou,Anton Devishvili,Jörg Sichelschmidt,Ioannis Panagiotopoulos,Aleksandr S Sukhanov,Victor Ukleev,Alexei Vorobiev

doi:10.3390/nano11010251

Abstract

Magnetic Weyl semimetals are newly discovered quantum materials with the potential for use in spintronic applications. Of particular interest is the cubic Heusler compound Co2MnGa due to its inherent magnetic and topological properties. This work presents the structural, magnetic and electronic properties of magnetron co-sputtered Co2MnGa thin films, with thicknesses ranging from 10 to 80 nm. Polarized neutron reflectometry confirmed a uniform magnetization through the films. Hard x-ray photoelectron spectroscopy revealed a high degree of spin polarization and localized (itinerant) character of the Mn d (Co d) valence electrons and accompanying magnetic moments. Further, broadband and field orientation-dependent ferromagnetic resonance measurements indicated a relation between the thickness-dependent structural and magnetic properties. The increase of the tensile strain-induced tetragonal distortion in the thinner films was reflected in an increase of the cubic anisotropy term and a decrease of the perpendicular uniaxial term. The lattice distortion led to a reduction of the Gilbert damping parameter and the thickness-dependent film quality affected the inhomogeneous linewidth broadening. These experimental findings will enrich the understanding of the electronic and magnetic properties of magnetic Weyl semimetal thin films.

Highlights

Topological materials have attracted tremendous interest in condensed matter physics due to their unique electronic band states, which give rise to novel linear and nonlinear responses [1,2,3,4,5,6,7,8,9]
We systematically studied the structural, electronic and magnetic properties of high-quality heteroepitaxial L21 -ordered Co2 MnGa thin films grown on MgO(001)
Atomic force microscopy (AFM) images were collected in non-contact mode on an MFP-3D Origin+

Summary

Introduction

Topological materials have attracted tremendous interest in condensed matter physics due to their unique electronic band states, which give rise to novel linear and nonlinear responses [1,2,3,4,5,6,7,8,9]. Weyl semimetals constitute one class of such topological systems. They are characterized by a lack of inversion symmetry or broken time-reversal symmetry, resulting. Nanomaterials 2021, 11, 251 in two-fold degenerate band-touching points (Weyl nodes) with opposite chirality formed in momentum space [3,5,10,11,12]. Some ferromagnetic compounds were proposed to be time reversal symmetry breaking Weyl semimetals (WSMs). Examples of such materials are Heusler compounds [26,27,28] and kagome crystals [29,30,31]

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Results

Conclusion