Theoretical determination of transport properties of magnetic multilayer systems

Hertha Firnberg Position T 27 Transport properties of magnatic multilayers Claudia BLAAS 09.03.1999 The aim of this project is the theoretical determination of transport properties of magnetic multilayer systems. Multilayer systems composed of ferromagnetic and non-magnetic layers have many interesting properties from the point of view of basic research and at the same time they are highly promising for technological applications. Current applications include, e.g., magnetic and magnetooptical recording, non-volatile memories, and highsensitivity magnetic sensors to operate at low field (in computers) and at high field (in automobiles). We intend to improve the ab-initio theory of magnetic multilayer systems in predicting and explaining their transport and magnetooptical properties, i.e., calculating the giant magnetoresistance, tunneling magnetoresistance, and also the magnetooptical Kerr effect. This description will allow us to get a deeper understanding of complex processes underlying electron transport in magnetic multilayer systems. We aim at a reliable description of the complicated physical nature of magnetic multilayer systems, i.e., describing effects of interdiffusion at interfaces and of alloying in magnetic and nonmagnetic slabs or substrates, in addition, for transport properties relativistic effects have to be included. Our calculations are based on the spin-polarized relativistic screened Korringa-Kohn-Rostoker method for layered systems (two-dimensional translational symmetry) which uses the Kubo-Greenwood equation for the conductivity and the single-site coherent potential approximation to incorporate the effect of impurities on electrical transport. This approach allows us to compute resistivities and the magnetoresistance of magnetic multilayer systems with no adjustable parameters by simultaneously determining contributions coming from both the electronic structure and spin-dependent scattering off impurities. It also seems possible to generalize our theory for a treatment of the magnetooptical Kerr effect. This project will be performed at the Center for Computational Materials Science (CMS) in Vienna.