Magnetoresistance Effect in Thin Magnetic Structures

Abstract

Magnetoresistance (MR) has been used to study inhomogeneous magnetic structures in thin films. From a known phenomenological law, it is possible to calculate for a given orientation of magnetization the electric fields in two perpendicular directions, so that one can plot a magnetoresistive loop as a function of magnetization orientation. We have studied two cases. (a) The angle α between magnetization and applied field in ferro-antiferromagnetic structure. In this case we have studied experimentally the MR loop and the curves α = f(θ), where θ is the angle between magnetic field and unidirectional axis. These results are similar to torque balance measurements obtained on the same structures. (b) The dispersion value ε of the magnetization versus the angle between mean magnetization and easy axis in simple films. In general, the dispersion value ε had been measured for a particular angle between magnetization and easy axis φ(φ = π/2). By MR it is possible to obtain the results for all values of φ. Finally we have drawn the experimental curve ε = g(H) for φ = 0 in a high-dispersion film and found the dispersion varying roughly as ε = ε0[HK/(H + HK)].