Effects of easy axis direction on the magnetoimpedance properties of thin films with uniaxial anisotropy

In this paper, we investigate the effects of easy axis direction against magnetoimpedance elements on stepped impedance properties. The angle between the easy axis and the element width is changed from 0° to 90°, and we examine the resulting impedance profiles. The magnetic field at which impedance is highest shifts to a lower field with increasing easy axis angles, which can be explained by a bias susceptibility theory. On the other hand, stepped impedance changes appear for the elements with an easy axis angle in the range of 35°–75°. We confirmed the stepped impedance property through our observations that those impedance jumps occur at transitional points of domain structure between single and multi domains by domain observations. The area where the impedance shows relatively low value and the element has multiple domains becomes narrower with increasing easy axis angles, which can be explained qualitatively on the basis of a simplified domain structure model.