AC CONDUCTIVITY NEAR THE PHASE-TRANSITION POINTS OF KNO3 CRYSTAL

The AC conductivity shows anomalous temperature dependence, with thermal hysteresis, near the phase transition points along the c-axis of KNO3 crystal. The spectra of conductivity in the range from 50 Hz to 100 kHz on the complex conductivity plane show similar semicircles in phases III, II and I below ~ 160°C. The fractional power law behaviour has been found in the frequency variation in the real component of the complex conductivity above ~ 160°C in phase I. The relaxation time τ(T) can be evaluated from the experimental results. The behaviour of τ(T) shows stepwise variation, with thermal hysteresis, near the phase transition points and anomalous increase above ~ 160°C. © 1990, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.