Magnetism at spinel thin film interfaces probed through soft X-ray spectroscopy techniques

Abstract Magnetic order and coupling at the interfaces of highly spin polarized Fe 3 O 4 heterostructures have been determined by surface sensitive and element specific soft X-ray spectroscopy and spectro-microscopy techniques. At ambient temperature, the interface between paramagnetic CoCr 2 O 4 or MnCr 2 O 4 and ferrimagnetic Fe 3 O 4 isostructural bilayers exhibits long range magnetic order of Co, Mn and Cr cations which cannot be explained in terms of the formation of interfacial MnFe 2 O 4 or CoFe 2 O 4 . Instead, the ferrimagnetism is induced by the adjacent Fe 3 O 4 layer and is the result of the stabilization of a spinel phase not achievable in bulk form. Magnetism at the interface region is observable up to 500 K, far beyond the chromite bulk Curie temperature of 50–95 K.