Stoichiometry dependent phase transition in Mn-Co-Ga-based thin films: From cubic in-plane, soft magnetized to tetragonal perpendicular, hard magnetized
Abstract
Epitaxial thin films of Mn3-xCoxGa were grown on MgO by magnetron co-sputtering with different Co content. Dependent on the Co content tetragonal or cubic structures are obtained. The composition dependence of saturation magnetization MS and uniaxial magnetic anisotropy Ku in the epitaxial films were investigated. A high magnetic anisotropy Ku of 1.2 MJ m-3 was achieved for the Mn2.6Co0.3Ga1.1 film with low magnetic moment of 0.84 μB. The valence band spectra of the films were investigated mainly by hard x-ray photoelectron spectroscopy. The evidence of sharp states in the cubic case, which are smeared out in the tetragonal case, proof the existence of a van Hove singularity that causes a band Jahn-Teller effect accompanied by a tetragonal distortion. These differences are in well agreement to the ab-initio calculations of the electronic structure.
- Publication:
-
Applied Physics Letters
- Pub Date:
- December 2012
- DOI:
- 10.1063/1.4770303
- arXiv:
- arXiv:1211.2440
- Bibcode:
- 2012ApPhL.101x2406O
- Keywords:
-
- ab initio calculations;
- cobalt alloys;
- gallium alloys;
- Jahn-Teller effect;
- magnetic anisotropy;
- magnetic epitaxial layers;
- magnetic moments;
- magnetic transitions;
- manganese alloys;
- metallic epitaxial layers;
- permanent magnets;
- soft magnetic materials;
- sputter deposition;
- stoichiometry;
- valence bands;
- X-ray photoelectron spectra;
- 75.30.Kz;
- 68.55.at;
- 75.70.Ak;
- 81.15.Cd;
- 75.30.Gw;
- 71.20.Be;
- Magnetic phase boundaries;
- Other materials;
- Magnetic properties of monolayers and thin films;
- Deposition by sputtering;
- Magnetic anisotropy;
- Transition metals and alloys;
- Condensed Matter - Materials Science
- E-Print:
- Appl. Phys. Lett. 101, 242406 (2012)