Investigations on structural, Mossbauer, dielectric, and ferroelectric properties of La doped barium hexaferrite

Abstract

La substituted Barium hexaferrite, Ba(1-x)La(x)Fe12O19, (x = 0, 0.1, 0.15, 0.20) was synthesized using ball milling followed by heat treatment. Rietveld analysis of X-Ray diffraction patterns reveals the formation of a single-phase magnetoplumbite structure of barium hexaferrite for all prepared samples. Morphological studies using FESEM shows the formation of hexagonal plate-like grains with different grain size, and the average grain size decreases with La doping. Elemental analysis using EDS confirms that the observed elemental composition for all the samples is within the expected range within the experimental error. Density measurements observed that porosity decreases up to La content x = 0.15 and then slightly increases for x = 0.20. Mössbauer spectroscopy studies reveal no formation of Fe2+ ions but delocalization of electrons after La doping. There is not much variation in the hyperfine structure with La doping. It is observed from the dielectric spectroscopy that the highest dielectric constant and low loss are observed for La content x = 0.20. The P-E loop of the pristine sample shows small polarisation but leaky behavior, whereas La substitution shows both leaky and resistor circuit-type behavior but large polarization.