Abstract
Surface/interface effect affects magnetization direction of nanosized magnets. Exchange magnetic anisotropy is a type of interface magnetic anisotropy between ferromagnet and antiferromagnet, which changes its direction by the direction of the antiferromagnetic spins on the interface. Thus, it is possible to control the magnetization direction of nanosized magnets coupled with antiferromagnet by controlling antiferomagnetic spin direction. α-Cr_2O_3 is chosen as an antiferromagnet. α-Cr_2O_3 possesses uniaxial anisotropy and shows magnetoelectronic effect. In this study, we report the structure and the magnetic behavior of ultrathin Co film grown on α-Cr_2O_3(0001) film. The ultrathin Co film has the perpendicular anisotropy and the perpendicular exchange anisotropy simultaueously. From the investigation on change in magnetic properties by neighboring material to Co, it is revealed that the perpendicular anisotropy is mainly induced at the interface of Au cap layer/Co but the Co/α-Cr_2O_3 interface also contribute the perpendicular anisotropy via collinear couplings of Co and Cr spins.
