Step feature observed in the angular dependence of magnetization switching fields in GaMnAs micro-device

Abstract

The magnetization switching phenomena of GaMnAs Hall devices have been investigated by using the planar Hall effect (PHE) measurement. Though two different sizes of Hall bar devices, width of 300 and of 10 mu m, show very similar Curie temperature, their magnetization switching fields behave significantly different. While the angle dependence of magnetization switching field of the 300 mu m device showed typical rectangular shape behavior with an applied magnetic field angle in the polar plot, that of the 10 pin device exhibited large step at (110) crystallographic directions, breaking the continuity of the switching field in angle dependence. Such unusual phenomenon observed in the 10 mu m device was discussed in terms of the change in magnetic anisotropy by the fabrication of micro-device. (c) 2008 Elsevier B.V. All rights reserved.