New Relaxors with the Perovskite Structure

Perovskites PbBO3 with multiple substitutions in the B-positions were synthesized. Ceramic samples with n = 2-6 (n is the number of different B-ions) were studied using X-ray diffraction, and measurements of dielectric permittivity at frequencies 12 Hz-100 kHz and temperatures 77-450 K. It has been shown that the samples are of the perovskite structure, they undergo phase transitions from disordered to ordered phase, and their dielectric behavior is typical for relaxors. The order-disorder phase transitions proceed with the unit cell doubling. Based on this and in accordance with random site model, the B-ion distribution over two sublattices is discussed.