Race track memories seen from an Ab initio point of view.

In using the fully relativistic versions of the screened Korringa-Kohn-Rostoker method and of the Kubo-Greenwod equation equilibrium domain wall widths and corresponding domain wall resistivities are calculated for CocFe1-c and CocNi1-c making use of a multiscale approach. It is found that in CocFe1-c the domain wall width becomes rather large at about c = 0.4, but does not show an obvious singularity in the vicinity of the bcc to fcc phase transition. In CocNi1-c the domain wall width varies much less in size with respect to the concentration. In particular, it is demonstrated that as compared to the homogeneous infinite systems the anisotropic magnetoresistance is reduced in the presence of a domain wall. This reduction is rather big for CocNi1-c, namely, about 6%, while for CocFe1-c it is only of the order of 1%-2%. The results clearly indicate that CocNi1-c might be a useful candidate for race track memories.