Structural, Dielectric and Ferroelectric Studies of Molybdenum Substituted Sr_2Bi_2Nb_2O_9 Ferroelectric Ceramics

摘要

In the present work, samples of compositions Sr_2Bi_2Nb_2O_9 and SrBi_2Nb_(1.9)Mo_(0.1)O_9 were prepared by solid state reaction method. X ray diffraction analysis reveals the formation of single phase perovskite structure. Although the perovskite structure of SBN is retained but slight change in the lattice parameters is observed. Dielectric constant and dielectric loss have been measured as a function of temperature (300 K-800 K) and frequency (1 kHz, 10 kHz and 100 kHz). Peak Dielectric constant is observed to increase from 465.05 for pure SBN to 613.17 for molybdenum substituted SBN while Curie temperature is observed to decrease from 420 deg C for pure SBN to 365 deg C for molybdenum substituted SBN. Dielectric loss is observed to increase from 0.066 for pure SBN to 0.123 for the doped sample at their respective Curie temperature. P-E loops have been recorded and retentivity and coercevity have been determined. The coercive field and remanant polarization values are observed to decrease from 10.647 mu zv/c.m. and 0.437 mu c/c.m.~2 for pure SBN to 8.989 mu v/c.m. and 0.338 mu c/c.m.~2 for molybdenum substituted SBN.