SYNTHESIS, STRUCTURAL CHARACTERIZATION AND PROPERTIES OF PEROVSKITE-TYPE MIXED OXIDES - BALNBNIO6 (LN = LA, ND, B = SB, NB, TA)

The materials BaLnBNiO6 (Ln=La, Nd; B=Sb, Nb, Ta) were obtained by thermal treatment of Ln(NO3)3.6H2O, BaCO3, NiCO3 and B2O5 in the temperature range 1473-1523 K. The crystal structure of BaNdSbNiO6 was refined by the Rietveld analysis of powder X-ray diffraction data. The unit cell is related to a GdFeO3 type perovskite with an ordered distribution of Sb and Ni ions (space group P2(1)/n, a=5.679(1), b=5.677 (2), c=8.045 (4) angstrom, beta=89.8(1)degrees; Z=2. The electrical conductivities of BaNdBNiO6 (B=Sb, Nb, Ta) have been measured over a wide temperature interval (300-1000-degrees-C). All these compounds are poor semiconductors. Magnetic susceptibility results suggest that none of these materials show long-range magnetic order in the temperature range measured.