Pyroelectricity and dielectric anisotropy in polarized and niobium modified barium titanate ceramics

Abstract

The effect of time of soaking on bulk density and dielectric constant has been measured on pure and niobium-doped barium titanate pyroelectric specimens. The temperature dependence of the dielectric constant for both pure and niobium-doped barium titanate samples has been investigated before and after poling. The percentage dielectric anisotropy and ferroelectricity was also calculated for various pure and modified barium titanate pyroelectric materials. Our results can be explained in terms of the redistribution of the barium titanate lattice in a different crystallographic orientation, polarization, as well as the existence of lattice imperfection accompanying temperature, poling and niobium doping. The obtained results were in good conformity, and correlated with the increased proportion of the remnant 90° domains (induced electrically charged vacancies as a result of Nb 3+ substitution of Ti 4+ in octahedral lattice sites). It was concluded that poling of Nb-doped barium titanate samples produces the best quality ceramic pyroelectrics.