An additional simultaneous magnetic ordering and magneto-capacitive behavior with dielectric relaxation besides multiferroicity in Fe1-xTexVO4.

Here we report the evidence of an additional magnetic ordering and frequency dispersive magneto-dielectric (MD) permittivity besides multiferroic behavior in Te4+(S= 0) doped FeVO4. Two antiferromagnetic transitions similar to FeVO4at ∼21.86 K (TN1) and 16.03 K (TN2) were observed in all samples. An additional novel defect clusters based magnetic ordering at relatively higher temperature (TAMO) ∼ 203 K is also observed from the magnetization. Evaluated magnetic moments show systematic decrease and the magnetic frustration factors show an increase with the increasing of Te4+(S= 0) content. MD studies show stable ferroelectric ordering at spiral magnetic transition (TN2) and the multiferroic order persists to the largest doping of Te (x= 0.10). The MD studies also reveal a magneto-capacitive (MC) behavior at TAMO(∼203 K) with a high dielectric constant and loss, and the possible reason for the magnetic ordering and MC behavior is ascribed to short range magnetic clustering arising out of defect based mechanisms. Mössbauer spectroscopic studies confirm local structural correlation with magnetic and ferroelectric ordering.

Polar state in polycrystalline BaSn0.3Ti0.7O3thin film determined from ac- & dc-field studies.

The present work reports polarization response and the effects ofac- &dc-fields on 30% Sn doped BaTiO3polycrystalline relaxor thin films as a function of temperature. Apart from the low temperature frequency dispersion in dielectric data, a frequency independent local maxima in dielectric constant and a concomitant peak in dielectric loss atT* ∼ 245 K is observed, which is unusual of bulk relaxor systems. BelowT*, dispersion in dielectric constant becomes quite evident showing signatures of non-ergodic behavior. Subsequently, the dielectric and polarization responses in ergodic (>T*) and non-ergodic (

Lattice assisted dielectric relaxation in four-layer Aurivillius Bi5FeTi3O15ceramic at low temperatures.

We have investigated magnetic, structural and dielectric properties of Bi5FeTi3O15(BFTO) in the temperature range 5K-300 K. Using diffraction, Raman spectroscopy and x-ray absorption fine structure measurements, iso-structural modifications are observed at low temperatures (≈100 K). The analysis of dielectric constant data revealed signatures of dielectric relaxation, concomitant with these structural modifications in BFTO at the same temperatures. Further, employing complementary experimental methods, it is shown that the distribution of Fe/Ti ions in BFTO is random. With the help of techniques that probe magnetism at various length and time scales, it is shown that the phase-pure BFTO is non-magnetic down to the lowest temperatures.