Dependence of the magnetic anisotropy on the ratio of the thicknesses of the magnetic and conductive layers

Control of the magnetic anisotropy is important for the sensitivity of giant Magnetoimpednace (GMI) magnetic sensors. Our research group proposed an effective magnetic anisotropy control method that uses inverse-magnetostriction and the difference in thermal expansion coefficients. If the proposed method is to be used, an investigation the ratio of the thicknesses between two layers (magnetic and conductive layers) is required because the sensitivity of proposed GMI sensor is determined by the ratio. In this paper, we introduce the dependence of magnetic anisotropy on the ratio of the thicknesses between the two layers to develop a GMI sensor with a high, and adjustable, sensitivity. The generated magnetic anisotropy (H _k(t)) in the magnetic layer depends on the shape anisotropy (H _k(s)) and the induced anisotropy (H _k(i)). To control the magnetic anisotropy, we change the thickness of the magnetic layer. The H _k(s), the H _k(i) and the generated bending stresses are numerically analyzed. In addition, the H _k(t) is obtained experimentally. Based on this study, we found H _k(t) to be inversely proportional to the stress.