Observation on Time Series Behavior of Ac Conductivity in Terbium Nitrate Crystal with Metastable Phenomena

Abstract

Time series data in ac conductivity at 2 kHz along the c -axis of terbium nitrate crystal with metastable phenomena have been measured at temperatures, -70° C≦ T ≦20° C, in sequent measuring runs. Non-periodic instability (burst) has been observed at those temperatures, as not in lighter rare earth nitrates. The limit cycles were found in the return map constructed from the time series behavior in unstable non-periodic time domain. Power spectrum densities derived from the data have showed characteristic properties of both broad random peaks and continuous spectrum proportional to 1/ f α (α=0∼2). Fractal dimensions have been given for the time series data in the stable fluctuated and the unstable non-periodic time domains.