Dielectric relaxation modes in bismuth-doped SrTiO3:: The relaxor behavior

The ferroelectric relaxer behavior in Bi-doped SrTiO3 was studied in the temperature range 1.5-300 K and up to 400 MHz. Some interesting results are shown: (1) Typical ferroelectric relaxer behavior develops out of the other impurity relaxation modes. The ferroelectric relaxer peaks occur on the quantum-paraelectric background. The polarization irreversibility effect observed after field cooling or zero-field cooling, and the data of remanent polarization P-r, show that the ferroelectric relaxer behavior is a nonequilibrium phenomenon. (2) The coexistence of the ferroelectric relaxer peak with other impurity modes indicates that there are several kinds of polar clusters which are responsible for different dielectric anomalies in different temperature ranges. This confirms a multicluster state characteristic in ferroelectric relaxors. (3) Near 400 MHz, an additional relaxation process appears. which indicates the possible existence of two polarization processes in a ferroelectric relaxer. [S0163-1829(99)03606-1].