Improved magnetoelectric effect in ytterbium doped BaTiO3 –CoFe2O4 particulate multiferroic composites

Abstract

The quest for multiferroic materials, where the phenomena of ferroelectricity and ferromagnetism are intimately coupled, is of great technological and fundamental importance. In this work, multiferroic particulate composites, (1-x) Ba0.95Yb0.05TiO3-xCoYb0.1Fe1.9O4 (x = 0.3, 0.6 and 0.9), were prepared by the solid-state reaction method. In all the composites, lattice parameters of CoYb0.1Fe1.9O4 phase decrease with the decrease in weight percentage of Ba0.95Yb0.05TiO3 phase. This effect resulted in an increase in the density and magnetoelectric effect of the composites. The dielectric loss and conductivity of composites was minimized, and a drop in Curie temperature was observed by doping ytterbium in the individual phases. The Austin-Mott model predicts that the conductivity can be attributed to the small range polaron hopping. The Mott conductivity dominates at low temperatures and disturbs the domain structure resulting in unsaturated P-E loops. The Law of approach was adopted to calculate the magnetocrystalline anisotropy, as all the composites were multidomain structured. The incorporation of ytterbium increased the magnetostriction in CoFe2O4 phase which results in an increase in magnetocapacitance of all the composites.