[21a-E216-1~4] 10.2 Fundamental and exploratory device technologies for spin

▼ [21a-E216-4] Control of perpendicular magnetic anisotropy of Co films formed on a flexible substrate by applying a biaxial tensile strain

〇Hiroki Matsumoto^1,2, Shinya Ota^1,2, Tomohiro Koyama^2,3, Daichi Chiba^2,3 (1.Univ. of Tokyo, 2.ISIR, Osaka Univ., 3.CSRN, Osaka Univ.)

Keywords:inverse magnetostrictive effect, flexible substrate, perpendicular magnetic anisotropy

Magnetization direction of ferromagnetic metal thin films deposited on a flexible substrate can be controlled by uniaxially stretching the substrate. If a tensile strain is induced by stretching it along the x axis, compressive strain is induced both in the y and z axes owing to the Poisson’s effect. In an fcc(111)-oriented Co film, the stretch-induced shrinkage in the out-of-plane direction is expected to induce a perpendicular magnetic anisotropy (PMA). This situation, however, is difficult to obtain as far as a uniaxial stretching is used because much larger in-plane magnetic anisotropy is induced along the stretched direction. To verify the inverse magnetostrictive effect due to shrinkage only in the thickness direction, here we use an in-plane biaxial stretching technique. As a result, we successfully demonstrate the stretch-induced magnetization easy axis switching from in-plane to out-of-plane in Co thin films sandwiched by Pd or Pt.