title: Co thin films deposited directly on ZnO polar surfaces.
abstract: A ferromagnetic (FM)-metal/oxide stack is the key structure determining the performance of spintronic devices. However, the effect of the electronic polarity of the oxide on the magnetic properties of the adjacent FM-metal has not been investigated previously. Here, we report the magnetic and structural properties of Co ultra-thin films sputter deposited directly on the Zn- and O-polar surfaces of ZnO substrates. The magnetic anisotropy and Curie temperature exhibit dramatic polarity-dependent differences for films on these surfaces. Structural analyses reveal that the heterointerface of the Co/O-polar surface is rather diffusive, whereas that of the Co/Zn-polar surface is atomically flat. These results suggest that the surface polarity plays a key role in determining the properties of the film. This novel FM-metal/polar-oxide system is expected to add new functionality to spintronic devices and provide an ideal basis for investigating the effect of a built-in electric field on the magnetism in a metallic monolayer.
authors.affiliation: Department of Applied Physics, The University of Tokyo, Bunkyo, Tokyo 113-8656, Japan.
authors.forename: Daichi
authors.initials: D
authors.lastname: Chiba
authors.affiliation: Institute of Engineering Innovation, The University of Tokyo, Bunkyo, Tokyo 113-8656, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Shibata
authors.affiliation: Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.|PRESTO, Japan Science and Technology Agency (JST), Chiyoda, Tokyo 102-0075, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tsukazaki