Influence of Surface Roughness on the Amplitude of Giant Magnetoresistance Effect in Multilayered Thin Films

Abstract

Since the discovery of one of the most engrossing advances in solid-state physics, the discovery of the giant magnetoresistance effect, the theoretical treatment of this effect has become the subject of much attention. It is considered that the amplitude of the effect depends on the degree of roughness of the outer and interlayer boundaries. Despite multiple experimental and theoretical studies, there is no consensus on the influence of outer boundaries and interfaces on the amplitude of the giant magnetoresistance. The need to resolve these contradictions should be carried out within the framework of an extended theoretical study of the giant magnetoresistance effect using more complex models for describing the interaction of charge carriers with the structure and interlayer boundaries. As an example, we have considered a three-layer film Fe/Cr/Fe consisting of ferromagnetic metal layers of different thicknesses separated by a nonmagnetic ultrafine metal layer. The results of numerical calculation within the framework of the semiclassical approximation show that the specular scattering of charge carriers by the interlayer and outer boundaries insignificantly increases the amplitude of the giant magnetoresistance effect because they do not lose their spin information when reflected from the surfaces. However, it should be noted that in the case when scattering centers are concentrated at the interlayer boundary, this leads to screening of charge carriers and, accordingly, to a decrease in the effect.