Measurements and simulation of hysteresis loops of donor-doped strontium bismuth tantalate ceramics

Wolframium ions doped SrBi2Ta2O9 ceramics have been synthesized by the conventional mixed-oxide method. A sawtooth-like hysteresis loop was observed at low measuring-frequency. This phenomenon was thought to be related with the perturbation of the defect-dipole polarization under an external electrical field. A developed physical-model was derived on the basis of simplifying such perturbation to a simple harmonic pendulum oscillator, which combines physical considerations with the well-known Preisach model. On the hypothesis of the simple harmonic pendulum oscillator, the included-angle between the defect-dipole polarization and the elementary-dipole polarization can be expressed as the product of the defect-dipole relaxation velocity and permitted relaxation time. Simulation result was excellently agreed with the observed measurement. (C) 2003 Elsevier B.V. All rights reserved.