Intrinsic Magnetic Proximity Effect at the Atomically Sharp Interface of Co x Fe3-x O4/Pt Grown by Molecular Beam Epitaxy

Co (x) Fe3-x O4(CFO)/Pt bilayers prepared by molecularbeam epitaxywere investigated for the anomalous Hall effect and X-ray magneticcircular dichroism (XMCD). We found that the anomalous Hall effectoriginates from a magnetic proximity effect at the CFO/Pt interface.The XMCD signal in the Pt L-edge was obtained onlyfor the sample deposited at 600 & DEG;C, indicating that the magneticproximity effect is sensitive to the interface structure. Transmissionelectron microscopy images of the CFO/Pt interface and XMCD measurementsof Co and Fe L-edges do not provide direct evidencefor interfacial atomic diffusion or alloying. In summary, these resultssuggest that the magnetic proximity effect is robust for transportproperties, such as the anomalous Hall effect, while the induced magneticmoment depends on slight differences in the interfacial structure,such as the presence or absence of interfacial oxygen ions.