Strain Mediated in-Plane Uniaxial Magnetic Anisotropy in Amorphous CoFeB Films Based on Structural Phase Transitions of BaTiO_3 Single-Crystal Substrates

摘要

The uniaxial in-plane magnetic anisotropy constants (K_1) of amorphousrnCo_(10)Fe_(74)B_(16) (CoFeB) films deposited on BaTiO_3 (BTO) single-crystal substratesrnare characterized using a vibrating sample magnetometer. As a result, arnsignificant increase in K1 with temperature is observed by a factor of 26, fromrn0.267×10~5 erg cm~(+3) at 300 K to 6.88×105 erg cm~(+3) at 230 K, and the thermal/K_1rncycling was reproduced. Estimation of the magnetoelastic effect at the CoFeB/rnBTO interface demonstrated that the external stress resulting from the structuralrnphase transition from tetragonal to orthorhombic structure in the (001) plane ofrnBTO substrate is the primary cause of the instant magnetic anisotropy inrnamorphous systems with isotropic magnetostriction such as CoFeB.