Control of in-plane uniaxial anisotropy of Fe ₇₂Si ₁₄B ₁₄ magnetostrictive thin film using a thermal expansion coefficient

This paper introduces an in-plane uniaxial anisotropy control method of Fe ₇₂Si ₁₄B ₁₄ magnetostrictive thin-film for high sensitivity of MI sensor. The anisotropy can be controlled by inverse-magnetostriction and inducing a bias stress using the difference of thermal expansion coefficient in bimetal structure. We can control the uniaxiality of anisotropy by the structure of the thin-film. Our proposed methods are useful in solving the problems and inconveniences of existing methods. To verify the proposed methods, we carried out experiments as well as FEM simulation. Looking at the FEM simulation and magnetic domain observation results, we confirmed that the in-plane uniaxial anisotropy could be controlled by a difference of a thermal expansion coefficient. Moreover, changes in the length of the conductive layer provides the local (edge section) control of the uniaxial anisotropy.