Structural, electric, magnetic, atomistic and electronic structure studies of cation-doped bulk and nanocrystalline iron-containing spinels and perovskites.

The electric and magnetic properties of iron-containing oxides with spinel and perovskite structures are attractive both scientifically and technologically. These properties can be tailor-made for specific applications when the materials are suitably doped or when their particle size is reduced to the nanometer scale. Cation doping is mostly performed using the conventional ceramic technique where high temperatures (andgt;1000andordm;C) are used. These high temperatures affect the electric and magnetic properties of the materials considerably due formation of other impurity phases or the reduction of ions within the materials (e.g. Fe3+ to Fe2+) thus posing a limit to their technological usefulness. To avoid such drawbacks, we intend here to synthesize bulk and nanocrystalline pure and doped spinel and perovskite materials at low temperatures by combining hydrothermal and mechanochemical (ball milling) preparation techniques followed by mild sintering. Our previous research has shown this approach to result in the production of the desired materials in the form of nanopartiles or bulk material depending on the sintering temperature and duration. We also intend to experimentally investigate the structural magnetic and electric properties of the prepared materials using the available techniques such as x-ray diffraction, x-ray photoelectron spectroscopy, electron and atomic force microscopy, Mandouml;ssbauer spectroscopy, magnetometry and electric measurements. In certain cases we intend to use computer codes to perform atomistic and ab inito electronic structure calculations to rationalize structures and the observed properties and also predict others.