Effect of interface on epitaxy and magnetism in h-RFeO3/Fe3O4/Al2O3 films (R=Lu, Yb)

We have carried out the growth of h-RFeO3 (001) (R=Lu, Yb) thin films on Fe3O4 (111)/Al2O3 (001) substrates, and studied the effect of the h-RFeO3 (001)/Fe3O4 (111) interfaces on the epitaxy and magnetism. The observed epitaxial relations between h-RFeO3 and Fe3O4 indicates an unusual matching of Fe sub-lattices rather than a matching of O sub-lattices. The out-of-plane direction was found to be the easy magnetic axis for h-YbFeO3 (001) but the hard axis for Fe3O4 (111) in the h-YbFeO3 (001)/Fe3O4 (111)/Al2O3 (001) films, suggesting a perpendicular magnetic alignment at the h-YbFeO3 (001)/Fe3O4 (111) interface. These results indicate that Fe3O4 (111)/Al2O3 (001) could be a promising substrate for epitaxial growth of h-RFeO3 films of well-defined interface and for exploiting their spintronic properties.