Structural, morphologic and dielectric properties of sodium ferrites

Abstract

Sodium ferrites powders were prepared by the sol-gel method. Discs were then prepared by molding, and different temperature treatments were done, between 400 and 1100°C, to densify the samples and to form the desired crystalline phases. Structural analysis was carried out using X-Ray diffraction, and morphologic studies using scanning electron microscopy. Impedance spectroscopy was used to the electrical characterization, in the frequency range from 100 Hz to 1 MHz, and temperatures between 100 and 400 K. From the point of view of dielectric relaxation, the modulus formalism was used, and several relaxation processes were identified. The sample with heat treatment of 1100°C presents the best results for energy storage, with a dielectric constant of 818, at 1 kHz and 300 K, with low losses. This is due to the increase of the dimensions of the grains.