Influence of additives on the structural, electrical and elastic properties of nanocrystalline MgCuZn ferrites

Abstract

Lead oxide (PbO) and Tantalum pentoxide (Ta2O5) added Mg0.2Cu0.3Zn0.5 Fe2O4 spinel ferrites are prepared by the microwave hydrothermal method. The prepared powders are characterized by powder X-ray diffraction (XRD), Infrared spectroscopy (IR), Transmission electron microscopy (TEM) and Differential scanning calorimeter (DSC). Monophase nanocrystalline ferrites of ~10 to 20nm size are prepared at a lower processing temperature of 160°C/1hour. The ferrites are sintered to a temperature of 900°C using microwave sintering (MW) method. The influence of additives on structure, densification, microstructure and electrical resistivity is studied. The addition of PbO to ferrite improves sintered density and resistivity compared to Ta2O5. The ultrasonic pulse transmission method is used to determine the elastic properties of the sintered ferrites. Elastic moduli such as Young's modulus (E), bulk modulus (B), modulus of rigidity (G), Poisson's ratio (σ) and Debye temperature (θD) are computed from the measured ultrasonic wave velocities. The elastic moduli of ferrite materials increase with PbO and decrease with Ta2O5 content, whereas Poisson's ratio almost remains constant. A linear relationship between Debye temperature and average sound velocity is observed.