Observation of magnetic domain structure in anatase (Ti,Co)O2 thin film at room temperature

Abstract

Magnetic domain structures in anatase (Ti,Co)O2 (001) epitaxial thin films were observed at room temperature. Magnetic force microscopy in vacuum enabled to observe submicrometer-sized maze domain. Variation of magnetic domain structure as functions of carrier density and Co content was in accordance with that of macroscopic magnetization representing close relationship between the bulk magnetism and magnetic domain structure. With increasing carrier density and/or Co content, the magnetic domain became larger with larger magnetic force signal mostly, where the ferromagnetic transition at carrier density of ∼2 × 1019 cm−3 was observed as an emergence of magnetic domain structure. Micromagnetic parameters were evaluated as functions of carrier density and Co content.