Structure and electronic states of single-crystal Fe_1-xNi_xO_y (0≤x≤1) thin films

In a previous report, we showed that a series of single-crystalline iron–nickel oxide alloy thin films, with various Fe–Ni concentration ratios, could be fabricated by a molecular beam epitaxy technique. With x-ray diffraction and adsorption studies, the distribution of Fe and Ni in these compounds are found different from a bulk Fe₂NiO₄ ferrite phase. We extend the study to a more detailed x-ray adsorption on oxygen K edge from these films. The new results again support the model of the unique ionic distribution in these ferrite alloy films. It further reveals a detailed hybridized feature with transition metal d and sp bands, which is sensitive to the local structure and near neighbors of Fe and Ni. This precisely characterized ionic structure can be directly compared to a local magnetic moment theory. A preliminary result of the magnetic response from these films is discussed. © 1999 American Vacuum Society.