Dresden 2006 – scientific programme

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MA: Magnetismus

MA 8: Surface Magnetism

MA 8.1: Talk

Monday, March 27, 2006, 15:00–15:15, HSZ 103

The magnetic surface of a non-magnetic bulk material: YCo₂(111) — •Josef Redinger¹, Sergii Khmelevskyi¹, Peter Mohn¹, and Michael Weinert² — ¹Inst. f. Allgemeine Physik, Vienna University of Technology, Getreidemarkt 9/134, A-1060 Vienna, Austria — ²Department of Physics, University of Wisconsin - Milwaukee, P.O. Box 413, Milwaukee, WI 53201, USA

A material with a magnetic surface and non-magnetic bulk would be highly desirable for technological applications since thin films of such a material would provide a natural magnetic multilayer with perfect matching of the electronic potentials at the magnetic/nonmagnetic interface. Using full-potential DFT calculations, we predict the existence of a stable magnetic (111) surface of the intermetallic compound YCo₂ which is nonmagnetic in the bulk with large magnetic moments in the topmost Co layer for both Y- and Co-terminated (111) surfaces. The magnetism does not extend beyond two Co layers, and despite a rather large contraction of the top Co-Y interlayer distance which tends to suppress magnetism, we find only a slightly reduced surface moment as compared to an ideal bulk truncated surface. The Y-terminated surface shows rather moderate interlayer relaxations, while intralayer relaxations are negligible for both terminations. The YCo₂(111) surface matches perfectly to Cu(111) thus facilitating the use of magnetically dead Cu cap layers, which will not kill the Co moments at the interface, according to our DFT results.

[1] S. Khmelevskyi, P. Mohn, J. Redinger, and M. Weinert, Phys. Rev. Lett. 94,146403 (2005)