Relaxation associated with the synergetic oxygen vacancies and electrons in (Ba1−xBix)0.9Sr0.1TiO3−δ ceramics

Abstract

The temperature dependence of dielectric properties of Bi-doped ceramics with (Ba0.95Bi0.05)0.9Sr0.1TiO3−δ and (Ba0.9Bi0.1)0.9Sr0.1TiO3−δ (abbreviated as BBST5 and BBST10, respec-tively) has been investigated, comparing with nondoped Ba0.9Sr0.1TiO3 (abbreviated as BST) ceramics. The dielectric relaxation behavior above 150 °C was observed in BBST5 and BBST10 ceramics with two broad dielectric loss peaks, which is very different from the BST ceramics with only one broad loss peak. The universal dielectric response (UDR) to the relaxation and P–E hysteresis loops, as well as J–E properties has been studied. The activation energy Ea with 0.83, 0.84 eV in the first dielectric loss peak P1 and 0.60, 0.65 eV in the second loss peak P2, and the exponent s in the UDR law decreasing with the increasing temperatures for BBST5 and BBST10 ceramics indicate that oxygen vacancies associated with electrons are responsible for the dielectric relaxation.