Influence of easy magnetization axis orientation on magnetization reversal in permalloy strips

Abstract

We studied the effect of easy magnetization axis orientation with respect to the strip direction on magnetization reversal process in permalloy strips by measuring the magnetoresistance (MR), the magneto-optic Kerr effect (MOKE), and the real-time domain evolution. The three strips were patterned on a single chip with the easy-axis orientation of each strip relative to the longitudinal direction by around 0, 30, and 60°, respectively. The overall shape of field-dependent MR was mostly governed by the anisotropic magnetoresistance. The longitudinal MR ratio was significantly increased with increasing angle between the easy axis and the bar direction. Several MR steps were observed during the magnetization reversal in 0 and 30° bars, and the simultaneous measurement of the MOKE and the domain images identified that the MR steps were associated with evolution of the magnetic domains. In addition a resistance contribution from the domain walls was also observed.