An interface between two non-magnetic metals turns magnetic: The case of YCo2(111)/Cu(111)

Thin films of a material with a magnetic surface and a non-magnetic bulk are natural magnetic multi-layers with a perfect matching of the electronic potentials at the magnetic/nonmagnetic interface. Using full-potential DFT calculations the existence of a stable magnetic (111) surface of the nonmagnetic bulk inter-metallic compound YCo2 was predicted, with large magnetic moments in the topmost Co layer for both Y- and Co-terminated (111) surfaces und subsequently verified experimentally. In the present contribution we focus on the interface between YCo2(111) and Cu(111). An almost perfect lateral match facilitates the growth of magnetically dead Cu cap or spacer layers. Our DFT studies predict that, despite a stable Y termination of the YCo2(111) surface, a Co/Cu interface with sizeable Co moments (averaged 0.8-0.9 μB) at the interface is formed, while Y floats on top. For YCo2/Cu(111) multilayers a similar magnetic behavior is predicted.