Interdependence between structure and electrical characteristics in Sm-doped barium titanate

Abstract

Conventional solid-state method was used to prepare powders of pure and barium titanate (BT) doped with different concentration of samarium. Influence of samarium addition on the structure modification, grain growth inhibition and microstructure development was studied. Dielectric properties of doped samples were significantly modified. With doping, a diffuse kind of ferro-para phase transition was induced, phase transitions positions were shifted and dielectric permittivity values were lowered in comparison with pure barium titanate. Detailed impedance and modulus data analysis were presented. The impedance complex plane showed two semicircular arcs for pure BT and one single depressed semicircular arc for all doped ceramics. Different electro-active regions in the modulus plane plots were also distinguish. The comparison between impedance and modulus scaling behavior presented the localized movement of charge carriers in the pure barium titanate and both, short and long range relaxations in the ceramics doped with 0.05 mol% of Sm. P-E hysteresis loops have shown the dilution of ferroelectric properties with Sm doping.