Temperature and frequency dependent dielectric properties of lithium orthophosphate LiBaPO4

The lithium barium orthophosphate LiBaPO4 compound has been synthesized by the classic ceramic method and characterized by X-ray diffraction (XRD) technique. The electrical conductivity and modulus characteristics of the system have been investigated in the temperature and the frequency range 681–872 K and 200 Hz–1 MHz respectively by means of impedance spectroscopy. The activation energy value of LiBaPO4 sample is bigger than of the LiMPO4 (M = Mn, Co, Ni, Fe) compounds. The frequency dependent conductivity of the present system shows the power law feature. Dielectric data were analyzed using complex electrical modulus M* at various temperatures. The peak positions ωm of the above spectra shift towards higher frequencies with increase in temperature. The above spectra have been characterized in terms of Kohlrausch–Williams–Watts (KWW) relaxation function to understand relaxation behavior. The activation energy responsible for relaxation calculated from the modulus spectra is found to be almost the same as the value obtained from temperature variation of dc conductivity. The electrical modulus and its scaling behavior are also investigated and the relationship between power-law exponent n and stretched exponential exponent β is found.

► We study the electrical properties of LiBaPO4.
► The frequency dependent conductivity of the present system shows the power law feature.
► The β parameter is correlated to the frequency exponent s by the relation β = 1 − n.