Synthesis and characterization of Sr3FeMoO6.88:: An oxygen-deficient 2D analogue of the double perovskite Sr2FeMoO6

We have prepared Sr3FeMoO6.88(1), an oxygen-deficient two-dimensional analogue of the double perovskite Sr2FeMoO6, and have investigated its structure and physical properties. According to powder X-ray and neutron diffraction data, Sr3FeMoO6.88 adopts the tetragonal n = 2 Ruddlesden-Popper structure (space group 14/mmm) with a completely disordered B-cation distribution and oxygen vacancies occurring preferentially at the axial 01 sites between the perovskite layers. X-ray absorption near-edge spectroscopy and Mossbauer data are consistent with trivalent Fe and mixed (4+/5+) Mo oxidation state. The compound is semiconducting, showing an intrinsic magnetic transition at similar to 85 K and an additional upturn in the magnetic susceptibility at similar to 270 K, the latter is associated with intergrowth defects. An appreciable magnetoresistance, reaching the value of similar to-15% at 5 K and 5 T is also observed.