Observation on Effect of Rare Earth Element on Time Series of AC Conductivities in Rare Earth Nitrate Crystals Having Metastable Phenomena

Abstract

Time series of ac conductivities at 2 kHz have been measured at 223.15 K for c-axis of the rare earth nitrate crystals R(NO₃)₃6H₂O, having the metastable phenomena, where R is rare earth element (R = ⁵⁷La, ⁵⁸Ce, ⁵⁹Pr, ⁶⁰Nd, ⁶²Sm, ⁶³Eu, ⁶⁴Gd, ⁶⁵Tb, ⁶⁶Dy, ⁶⁷Ho, ⁶⁸Er, ⁶⁹Tm, ⁷⁰Yb and ⁷¹Lu). The variation in the time series of the conductivities was found by changing the rare earth element in the crystal. The power spectral density P(f) derived from the time series data, shows dependence on frequency f, represented by power law P(f)∝f^−α and peak near the frequency f_Max. The numerical values of the exponent α and f_Max are dependent on the rare earth element sequence. The form of the function for f_Max to the sequence of R is similar to the magnetic characteristics.