Room Temperature Magnetic Properties of Fe/Co-Doped Barium Niobate Crystals

Perovskite-type structure BaNbO3 and Fe/Co-doped BaNbO3 nanocubes with a pure cubic phase have been synthesized by a composite-hydroxide-mediated method. X-ray diffraction and X-ray photoelectron spectroscopy reveal that Fe3+/Co2+ are incorporated into the BaNbO3 lattices. These doped samples exhibit smaller band gaps and semiconducting conduction quite different from the characteristics of BaNbO3. The resistivity is reduced 3-4 orders of magnitude after doping the BaNbO3 with Fe and Co ions. By comparing with the pure BaNbO3, we found that ferromagnetic property is achieved on the Fe/Co-doped BaNbO3 samples. The mechanism of magnetic property for Fe/Co-doped BaNbO3 is discussed by density functional theory, which provides an evident 3d transition metal doped easily in substitution of the B site element to produce ferromagnetism in ABO(3)-type ferroelectric semiconductor oxide. The report indicates that the 3d transition metal doped BaNbO3 may be a good candidate for new multiferroics.