The role of rare earth and transition metal cations doping on the structural and functional properties of Bi1-xYxFe0.7Mn0.3o3 magnetoelectric ceramics

Abstract

In this research, Bi1-xYxFe0.7Mn0.3O3 (x=0.00, 0.05, 0.10, 0.15 and 0.20) ceramics have been prepared by conventional solid state reaction method and sintered at 800, 825 and 875 oC. The prepared samples were characterized by the X-ray diffraction (XRD) analysis, Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray Spectroscopy (EDX). The electrical and magnetic properties were studied using Impedance Analyzer and vibrating sample magnetometer, respectively X-ray diffraction analysis ensured that the parent sample is crystallized in rhombohedra structure and Y- doping generates structural transformation toward orthorhombic structure due to the substitution of Y3+. The bulk density decreases with increasing Y content. The average grain size was found increasing with increasing Y content for sintered temperature 800, and 825oC but decreasing with increasing Y content for sintered temperature 850oC. From EDX analysis, Y content concentrates at the grain boundaries and that is increasing with increasing sintering temperature. Due to space charge polarization dielectric constant was observed to show dispersive behavior at lower frequency. Dielectric constant increased with the increasing Y content. From the impedance and AC conductivity measurement it is observed that the value of impedance decrease with increase in frequency and AC conductivity increased because of hopping of charge carriers. The electrical impedance of compressed disks was investigated by impedance analysis and the results were successfully fitted by a simple parallel R–C model. Impedance spectroscopy also showed that grain and grain boundary contribution is present in the conduction mechanism for x=0.00 and grain boundary resistance is increasing with Y content for x= 0.5-0.20. The real part of complex initial permeability, µi', of the samples increased with sintering temperatures because of uniform grain growth. Magnetoelectric coefficient was observed improving with Y doping in Bi1-xYxFe0.7Mn0.3O3 compositions.