Time Series of ac Conductivity in Praseodymium Nitrate Crystal

Time series of ac conductivity were measured at 2 kHz in the temperature region from 200 to 8 K along a direction perpendicular to the c -axis for a praseodymium nitrate crystal. Nonperiodic instabilities (bursts) were found in all the time series. Their power spectral densities showed a continuous spectrum proportional to 1/ f α . The correlation integrals were derived from the data. The temperature variation of both the power spectral densities and the correlation exponents at an embedding dimension was found in the three regions near 30, 80, and 150 K.