The crystalline phases of the synthesized samples were analyzed by X-ray diffraction

The crystalline phases of the synthesized samples were analyzed by X-ray diffraction(XRD) technique using powder X-ray diffractometer (Bruker AXS D8 Advance) with Cu-K? radiation (?= 1.5406Å) at 40kV and 35mA. Scanning from 10o to 80o at a step size of 0.02o per second was performed for each sample. The crystal structure, lattice parameter, crystallite size and X-ray density were determined. Elemental analysis was done using Energy Dispersive X-ray Spectroscopy (EDX) (Joel 6390LV). Scanning Electron Microscopy (SEM, VEGA3 TESCAN) and HRTEM were used to investigate the morphology of the synthesized mixed ferrite samples. Magnetic property characterization was carried out using Vibrating Sample Magnetometer (VSM, Lakeshore, USA, Model 7407) at room temperature and at 77K up to a maximum field of 15kOe. For AC conductivity and dielectric measurements using precision impedance analyser(WAYNE KERR 6500B), cylindrical pellets of the samples (13mm diameter and 2-3mm thickness) were made using a hydraulic press by applying a uniform pressure of 2.5 ton. Silver paste was used as electrode material. The frequency dependence of dielectric properties was studied in the frequency range 20Hz to 10MHz.