Dielectric relaxation in SrFe 1/2Nb 1/2O 3

Abstract

The strontium iron niobate Sr Fe12 Nb12 O3 ceramic is synthesized by a solid-state reaction technique. The x-ray diffraction of the sample at room temperature shows a monoclinic phase. The dielectric permittivity and the loss tangent of the sample are measured in a frequency range from 50 Hz to 2 MHz and in a temperature range from 143 to 473 K. The frequency dependence of the loss peak is found to obey an Arrhenius law with an activation energy of 0.272 eV. An analysis of the loss factor with frequency is performed by using the scaling behavior of the dielectric loss spectra. The scaling behavior of the dielectric loss spectra shows its temperature-independent nature. The relaxation mechanism is discussed in the framework of conductivity and impedance spectroscopy. The variation of dielectric constant with temperature is explained considering the space-charge polarization.