STRUCTURAL AND MAGNETIC-PROPERTIES OF THE ANION-DEFICIENT LAVO3-DELTA

The anion deficient LaVO3-delta (delta = 0.08) was prepared by solid state reactions using V2O3 and pre-dried La2O3 in an evacuated induction furnace. The oxygen content was estimated by thermogravimetric analysis (TGA). Rietveld profile analysis of powder X-ray diffraction data shows that this sample adopts an orthorhombically distorted perovskite structure, isostructural with GdFeO3; space group Pnma, a = 5.5509(1), b = 7.8441(2), c = 5.5513(s) Angstrom. Four probe resistivity measurements indicates that LaVO3-delta is semiconducting over the experimental temperature range. The magnetic properties of LaVO3-delta are strongly dependent on the sample cooling history. LaVO3-delta undergoes a paramagnetic to antiferromagnetic transition at ca. 140K under zero-field-cooled condition. When cooled in a magnetic field of H-appl less than or equal to 5 kG, however, the anomalous diamagnetic behaviour is observed below ca. 140 K. These properties are discussed in terms of the structure-property relationship, and comparisons are made to the previous results on the stoichiometric LaVO3.