Structural, microstructural, dielectric, electrical, and magnetic properties of a scandium-modified bismuth ferrite

Abstract

ABSTRACT This paper reports on the synthesis method and characterisation of a binary polycrystalline material (Pb0.6Bi0.2Sc0.2)(Fe0.4Ti0.6)O3 ceramic. The room temperature XRD pattern confirms an orthorhombic crystal structure with average crystallite size of 25.3 nm. Study on SEM micrograph reveals the homogeneous dispersal of grains and well-defined grain boundaries and also the compactness of the grains implies the development of a highly dense material. The purity and composition of this material are verified using EDX, and confirms presence of all the constituent elements (Pb, Bi, Sc, Fe, Ti, and O) both in weight and atomic percentage. According to research on dielectric spectra as a function of temperature range of 25°C to 500°C and frequency range of 1 kHz to 1 MHz, there may be Maxwell–Wagner-type dispersion at low frequencies, which considerably decreases towards higher frequencies because of decreasing space charge polarisation. The negative temperature coefficient of resistance behaviour is observed from impedance spectroscopy. The research of modulus spectroscopy demonstrates the existence of a non-Debye type of relaxation. The thermally activated charge carriers regulate the study of the conduction mechanism. The semicircular arcs found both in Nyquist and Cole–Cole plots provide an evidence for the semiconducting nature. The magnetic study reveals the superparamagnetic nature of the sample.