Investigation of the interfacial structure and transport properties of Fe3O4–SrTiO3 composite films

Abstract Interfacial structure, magnetic and transport properties of the (Fe 3 O 4 ) 1− x (SrTiO 3 ) x composite films prepared by cosputtering were investigated systematically. X-ray diffraction, scanning electron microscopy and transmission electron microscopy analyses indicate that the nanosized Fe 3 O 4 grains embedded in amorphous SrTiO 3 matrix with well-defined interfaces. The X-ray photoelectron spectroscopy and zero-field-cooling and field-cooling curves reveal that the composite films have very light interfacial diffusion. The composite films exhibit room temperature ferrimagnetism and enhanced resistivity with increasing x . The tunneling transport of the conduction electrons across the grain boundaries causes negative tunneling magnetoresistance of 6.9% for x = 0, and 3.3% for x = 0.13 at 50 kOe.