Magnetoelectric coupling susceptibility in novel lead-free 0–3 type multiferroic particulate composites of (1-x)Na0.5Bi0.5TiO3 -(x)CoCr0.4Fe1.6O4

Abstract

Lead-free 0–3 particulate composites of chromium substituted cobalt nano-ferrite CoCr0.4Fe1.6O4 (CCFO) and sodium bismuth titanate Na0.5Bi0.5TiO3 (NBT) having molar ratio of (1-x)Na0.5Bi0.5TiO3 -(x)CoCr0.4Fe1.6O4 (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5& 1) have been investigated. XRD patterns reveal that the composites crystallized with binary rhombohedraland cubic phase, equivalent to room temperature crystal symmetry of host ferroelectric NBT and magnetic CCFO materials, respectively. SEM micrographs depict the presence of both parent phases with different micro-structural symmetries. The observed ferroic properties, derived from isothermal magnetization and polarization measurements, emphasize that all the (1-x)NBT - (x)CCFO compositions exhibit significant sensitivity towards the magnetic field as well as the electric field. To evaluate the degree of magnetoelectric coupling in CCFO-NBT composites, we employed the magneto-dielectric characterization technique as a sensitive probing tool. We note that magneto-dielectric property initially increases with x and is found to be maximum ∼ −0.78% (x = 0.4) and further decreases with x. This unconventional product behaviour of particulate composite system is availed through magnetostrictive nature of magnetic subsystem - CFO and piezoelectric characteristics of ferroelectric- NBT. These lead-free multiferroic composites may provide an opportunity for the miniaturization of environmental-friendly magnetoelectric (ME) devices.