Theoritical and experimental investigation of AC conduction of K2CaV2O7

摘要

K₂CaV₂O₇ pyrovanadate was prepared by the simple solid-state method at high temperature. The analysis of x-ray data reveals that the sample crystallize in the triclinic system. Observed vibrational modes confirm the existence of V207 functional group. Analysis of DSC data show the presence of phase transition at T=627 K. Electrical data have been obtained using complex impedance spectroscopy (CIS) in the frequency of 209 Hz-1 MHz and temperature range of 609-725 K. Nyquist plots show the existence of tow contributions, an equivalent circuit was suggested. DC conductivity profile shows that electrical conduction in the material is a thermally activated process and confirms the phase transition obtained by DSC analysis. The analysis of AC conductivity data proved that CBH conduction mechanism is the most suitable to describe the frequency and temperature behaviour of charges carriers.