Domain walls and domain wall resistivities in Co_xPd_1−x(111) and Co_xPt_1−x(111)

Abstract

In using the relativistic screened Korringa–Kohn–Rostoker method and a multi-scale approach based on a parametrization of the Ginzburg–Landau expansion of the free energy as a functional of the magnetization density, domain wall widths in Co _x Pd_1−x and Co _x Pt_1−x are determined by considering these substitutionally disordered alloys as two-dimensionally invariant systems. It is shown that in Co _x Pd_1−x , domains are formed nearly over the whole concentration range, while in Co _x Pt_1−x , domain wall formation only occurs near 50% Co and for Co-rich alloys. Based on these results resistivities in the presence and absence of domains walls are evaluated in terms of the relativistic Kubo–Greenwood equation. In contrast to Co _x Ni_1−x , it turns out that both systems are unsuitable as race track materials.

Keywords:

• magnetic structure
• magnetic alloys
• electrical transport
• magneto-resistance

Acknowledgements

This paper is dedicated to my friend Jim Smith on the occasion of his 65th birthday. He not only insisted that I became an associate editor of Philosophical Magazine quite a few years ago, but he also facilitated many enjoyable summers in Los Alamos for me (working in the lab) and my family. After all these extended visits to Los Alamos, New Mexico became as familiar to us as our own home country. Occasionally it is quite appropriate to say thank you!