Study of structural, electrical and magnetoelectric properties of polycrystalline Bi1-xGdxFe0.9Cr0.1O3

Abstract

In this research, polycrystalline Bi1-xGdxFe0.9Cr0.1O3 (x = 0.00, 0.05, 0.10, 0.15 and 0.20) ceramics have been synthesized by standard solid state reaction technique. The structural, microstructural, electrical, magnetic and magnetoelectric properties of various Bi1-xGdxFe0.9Cr0.1O3 have been studied. X-ray diffraction analysis confirmed the structural transformation from rhombohedral to orthorhombic for x = 0.10. Microstructural and quantitative analysis were performed by Field Emission Scanning Electron Microscope and Energy Dispersive X-ray spectroscopy respectively. Average grain size was found decreasing with increasing Gd content due to grain growth suppression by Gd and it was found increasing with sintering temperature. At lower frequency, dielectric constant showed dispersive behavior due to space charge polarization. Dielectric constant increased with increasing Gd content. From the impedance and AC conductivity measurements it is observed that the value of impedance decreases and AC conductivity increases with increasing frequency because of hopping of charge carriers. Impedance spectroscopy also showed that both grain and grain boundary contribution are present in the conduction mechanism and resistance is found decreasing with Gd content. The conduction phenomenon also understood from the electric modulus (M′) vs frequency graph. M′ approaches to zero in the lower frequency region and a continuous dispersion on increasing frequency may be contributed to the conduction phenomenon due to short range mobility of charge carriers. The real part of complex initial permeability (i′) of the samples increased with sintering temperature because of uniform grain growth. Improved magnetization was found in Gd doped Bi1-xGdxFe0.9Cr0.1O3 due to magnetic property of Gd. Magnetoelectric coefficient was observed to improve with Gd doping in Bi1-xGdxFe0.9Cr0.1O3 compositions and it also increased with increasing sintering temperature.