Effect of frequency of the alternating electric field on temperature impedance spectra of LuFe$_{2}$O$_{4}$ ceramic multiferroic

Temperature impedance spectra are measured on LuFe$_{2}$O$_{4}$ ceramic multiferroics over a temperature range of 100–400 K, upon applying a sinusoidal voltage with a frequency varying between 20 Hz and 120MHz. At signal frequencies of 30–70 MHz, spectra exhibit features such as an abnormal positive temperature resistance coefficient within the temperature range of 200–260 K, which are interpreted in the context of the generalized barrier model.