Induction of large in-plane uniaxial magnetic anisotropy for Co-Fe-B-Pt thin films by magnetic field annealing

山崎 匠*; 石谷 優剛*; 中田 勝之*; 佐々木 智生*; 遠藤 恭*; 高梨 弘毅; 関 剛斎*

Yamazaki, Takumi*; Ishitani, Yugo*; Nakada, Katsuyuki*; Sasaki, Tomoyuki*; Endo, Yasushi*; Takanashi, Koki; Seki, Takeshi*

The induction of large in-plane uniaxial magnetic anisotropy for the CoFeB-based thin films by post-annealing under the magnetic field application is reported. The comprehensive study reveals the influence of CoFeB composition and Pt addition to CoFeB on the induced magnetic anisotropy by magnetic field annealing. The addition of Pt to a CoFeB film significantly enhances the effect of magnetic field annealing, and as a result, the CoFeB-Pt films exhibit the in-plane uniaxial magnetic anisotropy energies that are one order of magnitude larger than the pristine CoFeB films. In order to understand the mechanism of magnetic anisotropy induction by post-annealing, the magnetostriction measurement for the CoFeB-based thin films were carried out. The correlation between the induced magnetic anisotropy and magnetoelastic properties is discussed.