Multiferroic and magnetodielectric properties of (1-x)KNN-xCMgFO ceramic-based composites

Abstract

ABSTRACT The multiferroic composite ceramics of (1-x)[K0.5Na0.5NbO3]-x[Co(Mg0.05Fe1.95)O4]; x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5 and 1.0 have been synthesized by solid-state route. The effect of stoichiometric proportions on their structural, morphological, ferroelectric, dielectric, magnetic and magnetodielectric properties has been explored in detail. The dual phase formation in the XRD pattern has revealed the presence of orthorhombic and spinel cubic structures of KNN and CMgFO, respectively. SEM investigations indicated the cuboidal shaped grains of KNN, while agglomeration has been observed for CMgFO. All the composites have found to exhibit ferromagnetic ordering, where Ms continuously increases with increasing CMgFO concentration (~9 to 41 emu/g for x = 0.1 to x = 0.5); however, ferroelectric nature of composites decreases with increasing CMgFO concentration. The dielectric constant decreases, while loss increases with increasing ferrite concentration, except for x = 0.5. The decrease in dielectric constant with magnetic field is an evidence of magnetodielectric (MD) effect, with MD values of −3.5%, −3.6%, −4.5%, −10.3% and −5.2% for x = 0.1, 0.2, 0.3, 0.4 and 0.5, respectively. The maximum value of MD ~ −10% for x = 0.4 composite, indicated the appreciable ME coupling effect between ferroelectric and ferromagnetic phases, in present research work.