Dielectric, magnetic and humidity properties of Mg–Zn–Cr ferrites

Abstract

Abstract In this study, Cr3+ substituted Mg0.75Zn0.25CrxFe2-xO4 (x = 0, 0.1, 0.3) (Mg–Zn–Cr) ferrites have been synthesized using chemical co-precipitation method. The crystal structure and phase formation of Mg–Zn–Cr ferrites have been analyzed by X-Ray diffraction (XRD) method. The crystal size (from 15.37 nm to 10.84 nm) and lattice constant (from 8.405 A to 8.384 A) of the crystallized in cubic crystal structure Mg–Zn–Cr samples decreased with Cr3+ contribution. The change in lattice strain determined by Williamson-Hall (W–H) graphs. Morphological and elemental analysis were investigated using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy. The variations in temperature-dependent dielectric properties of samples between 290 K and 700 K were examined in the range from 20 Hz to 10 MHz. Curie temperature, where maximum dielectric constant is observed, shifted low temperatures with increasing Cr3+ contribution. This peak shift indicates that the materials have a relaxor ferroelectric character in accordance with the literature. Impedance analysis of Mg–Zn–Cr ferrites were investigated using Nyquist curves and relaxation process confirms Cole-Cole model. The magnetic properties of the samples in the range of ±5 kOe at 300 K were examined with the help of the Vibrating Sample Magnetometer (VSM). The M − H hysteresis loops of all samples showed the characteristic properties of soft magnetic materials. Finally, the effect of relative humidity (%RH) on the impedance of samples for different frequency values was investigated.