Conduction and dielectric behavior of ${\mathrm{Sr}}_{0.97}\left({\mathrm{Ti}}_{1-x}{\mathrm{Fe}}_x\right){\mathrm{O}}_{3\mathrm{-}\mathrm{\delta }}$ solid solutions were studied. The temperature dependence of the dc conductivity with $\sigma \propto A\exp \left(-{\mathrm{BT}}^{1/4}\right)$ obtained, indicated a variable-range hopping mechanism. A low-frequency dielectric relaxation was also observed. The activation energy for the variable-range hopping conduction is slightly higher than that for dielectric relaxation, suggesting that the dielectric relaxation is due to the trap-controlled ac conduction.

• Received 9 December 1997

DOI:https://doi.org/10.1103/PhysRevB.57.11858