All oxide ferromagnet/semiconductor epitaxial heterostructures

Oxide based ferromagnet/semiconductor heterostructures offer substantial advantages for spin electronics. We have grown (111) oriented Fe3 O4 thin films and Fe3 O4 /ZnO heterostructures on ZnO(0001) and Al2 O3 (0001) substrates by pulsed laser deposition. High quality crystalline films with mosaic spread as small as 0.03°, sharp interfaces, and rms surface roughness of 0.3 nm were achieved. Magnetization measurements show clear ferromagnetic behavior of the magnetite layers with a saturation magnetization of 3.2 μB /f.u. at 300 K. Our results demonstrate that the Fe3 O4 /ZnO system is an intriguing and promising candidate for the realization of multifunctional heterostructures.