Magnetic and Electronic Properties of Weyl Semimetal Co2MnGa Thin Films

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

doi:10.3390/nano11010251

Magnetic and Electronic Properties of Weyl Semimetal Co₂MnGa Thin Films

Nanomaterials (Basel). 2021 Jan 19;11(1):251. doi: 10.3390/nano11010251.

Authors

Peter Swekis^{1

2}, Aleksandr S Sukhanov^{1

2}, Yi-Cheng Chen^{1

3}, Andrei Gloskovskii⁴, Gerhard H Fecher¹, Ioannis Panagiotopoulos⁵, Jörg Sichelschmidt¹, Victor Ukleev⁶, Anton Devishvili^{7

8}, Alexei Vorobiev⁸, Dmytro S Inosov², Sebastian T B Goennenwein^{2

9

10}, Claudia Felser¹, Anastasios Markou¹

Affiliations

¹ Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany.
² Institut für Festkörper- und Materialphysik, Technische Universität Dresden, 01062 Dresden, Germany.
³ Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan.
⁴ Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany.
⁵ Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina, Greece.
⁶ Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, 5232 Villigen, Switzerland.
⁷ Institut Laue Langevin, 38000 Grenoble, France.
⁸ Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden.
⁹ Center for Transport and Devices of Emergent Materials, Technische Universität Dresden, 01062 Dresden, Germany.
¹⁰ Department of Physics, University of Konstanz, 78457 Konstanz, Germany.

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.

Keywords: Heusler compounds; ferromagnetic resonance; magnetic Weyl semimetals; magnetic anisotropy; magnetic dichroism; photoelectron spectroscopy; polarized neutron reflectivity; thin films; topological materials.