The temperature dependence of dielectric properties and electrical conduction of $\left({\mathrm{Sr}}_{1-1.5x}{\mathrm{Bi}}_x\right){\mathrm{TiO}}_3\hspace{0.5em}(0.0133\mathrm{}<~x<~0.133)$ was measured from 10 to 800 K. Three sets of oxygen vacancies related dielectric peaks (peaks A, B, and $C)$ were observed. These peaks could be greatly suppressed or eliminated by annealing the samples in an oxidizing atmosphere, and enhanced or recreated by annealing in a reducing atmosphere. The results show that the Maxwell-Wagner polarization is not the main mechanism, and the Skanavi’s model also cannot be directly applied. A tentative explanation was suggested. Peak A, observed in the temperature range of 100–350 K with the activation energy for dielectric relaxation $E_{\mathrm{relaxA}}=0.32\mathrm{}–0.49$ eV, is attributed to the coupling effect of the conduction electrons with the motion of the off-centered Bi and Ti ions; the conduction carriers in this temperature range are from the first ionization of oxygen vacancies ${(V}_o).\mathrm{}$ Peaks B and C are also discussed.

• Received 23 December 1999

DOI:https://doi.org/10.1103/PhysRevB.62.228