  Oxide based ferromagnet/semiconductor heterostructures offer substantial
advantages for spin electronics. We have grown (111) oriented Fe3O4 thin films
and Fe3O4/ZnO heterostructures on ZnO(0001) and Al2O3(0001) substrates by
pulsed laser deposition. High quality crystalline films with mosaic spread as
small as 0.03 degree, 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 muB/f.u. at 300 K.
Our results demonstrate that the Fe3O4/ZnO system is an intriguing and
promising candidate for the realization of multi-functional heterostructures.
