Low temperature pyroelectric behaviour of barium titanate

Abstract

The pyroelectric and dielectric properties of barium titanate crystals have been investigated in the temperature range from 300K to 150K. The pyroelectric coefficient has peaks at the tetragonal-orthorhombic transition and at the orthorhombic-rhombohedral transition. A thermal hysteresis of about 10K is recorded for the T-O transition and one of about 15K for the O-R transition. In the temperature range near the phase transitions, an unusual pyroelectric response was observed. Following a temperature variation, the pyroelectric charge changed its polarity with time. This behaviour can be attributed to the coexistence of two ferroelectric phases.