EFFECTS OF SURFACE ROUGHNESS ON THE GIANT MAGNETORESISTANCE PERFORMANCE IN MAGNETIC SANDWICHES

Since the discovery of Giant magnetoresistance, the theoretical treatment of this effect became the subject of much attention. It is one of the most engrossing discoveries in thin-film magnetism, which combines both huge technological potential and deep fundamental physics. It is considered that the effect of giant magnetoresistance is due to the spin-dependent scattering of charge carriers in the volume of magnetic layers and at their boundaries, and its amplitude depends on the degree of roughness of the outer and interlayer boundaries. Despite a large number of both experimental and theoretical works, in which the influence of the state of outer boundaries and interfaces on the magnitude of the giant magnetoresistance was studied, conclusions do not coincide [1-5]. 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. This was the subject of our study. 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 shown that the specular scattering of charge carriers by the interlayer and outer boundaries insignificantly increases the amplitude of the giant magnetoresistance effect due to the fact that 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.