Stoichiometry dependent phase transition in Mn-Co-Ga-based thin films: From cubic in-plane, soft magnetized to tetragonal perpendicular, hard magnetized

Journal Article · Mon Dec 10 00:00:00 EST 2012 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4770303· OSTI ID:22089591

Ouardi, Siham; Fecher, Gerhard H.; Stinshoff, Rolf; Felser, Claudia ^[1]; Kubota, Takahide; Mizukami, Shigemi; Miyazaki, Terunobu ^[2]; Ikenaga, Eiji ^[3]

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1. Max Planck Institute for Chemical Physics of Solids, 01187 Dresden (Germany)
2. WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai 980-8577 (Japan)
3. Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo 679-5198 (Japan)

Epitaxial thin films of Mn{sub 3-x}Co{sub x}Ga 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 M{sub S} and uniaxial magnetic anisotropy K{sub u} in the epitaxial films were investigated. A high magnetic anisotropy K{sub u} of 1.2 MJ m{sup -3} was achieved for the Mn{sub 2.6}Co{sub 0.3}Ga{sub 1.1} film with low magnetic moment of 0.84 {mu}{sub B}. 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.

• OSTI ID: 22089591
• Journal Information: Applied Physics Letters, Vol. 101, Issue 24; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANISOTROPY
COBALT COMPOUNDS
ELECTRONIC STRUCTURE
EPITAXY
GALLIUM COMPOUNDS
HARD X RADIATION
JAHN-TELLER EFFECT
MAGNESIUM OXIDES
MAGNETIC MATERIALS
MAGNETIC MOMENTS
MAGNETIZATION
MAGNETRONS
MANGANESE COMPOUNDS
PERMANENT MAGNETS
PHASE TRANSFORMATIONS
SPECTRA
SPUTTERING
STOICHIOMETRY
THIN FILMS
X-RAY PHOTOELECTRON SPECTROSCOPY