Abstracto

Study of the Dielectric Variation Due To Phase Transformation in Substituted Spinels

P.G. Bhatia

Pseudobrookite Fe2TiO5 was reduced to a spinel by substituting Fe 2+ by Li+ & Ti4+ by Ba2+ and the role of Ba2+, Ti4+ on the oxide samples was studied. Spinel samples, Li0.9Fe1.1Ba0.1Ti0.9O4 (SP1) and Li0.7Fe1.3 Ba0.3Ti0.7O4 (SP2) were prepared by the solid state reaction method. The single phase spinel structure was confirmed using XRD technique and lattice constants were determined. With the increase in Barium content, the symmetry was seen to undergo a change from cubic to tetragonal phase. The cation distribution in the samples was determined. Ba was seen to show a strong preference for the tetrahedral (A) sites. The dielectric constant was measured by varying frequency from 1 Khz to 1 Mhz and in the temperature range from 300oK to 773oK. The tetragonal spinel was observed to show a huge dielectric constant as compared to the cubic spinel. The enhanced dielectric constant makes it a promising battery material and could be studied against the backdrop of phase transformation.