Modulus Spectroscopy of Potassium Lithium Niobate (K₃Li₂Nb₅O₁₅) Single Crystal

抄録

The modulus spectroscopy of potassium lithium niobate (KLN) crystals was investigated in the frequency range from 100 Hz to 10 MHz and temperature range from 30°C to 600°C. The dielectric anomaly with a broad peak was observed around 430°C. The ac conductivity is frequency dependent at low temperatures such as σ=σ_dc+Aω^s, and shows a frequency independent at low frequencies and high temperatures. The electrical relaxation in ionically conducting KLN crystal analysed in terms of modulus formalism. The electric modulus which describes the dielectric relaxation behavior is fitted to the Kohlrausch-Williams-Watts (KWW) exponential function. Near the phase transition temperature, a stretched exponential parameter β indicating the degree of distribution of the relaxation time has a small value. The activation energy near the phase transition temperature is different from that of above and below phase transition temperature. The temperature dependence of the electric modulus is studied and the results are discussed.