Large converse magnetoelectric effect in Na0.5Bi0.5TiO3-CoFe2O4 lead-free multiferroic composites

Lead-free multiferroic composites of ferroelectric, Na0.5Bi0.5TiO3 (NBT) and ferrimagnetic, CoFe2O4 (CFO) were synthesized by the solid-state sintering method and a systematic study of structural, magnetic, and magnetoelectric properties was undertaken. X-ray diffraction and field emission scanning electron microscopy displayed the formation of single phase for parent phases and the presence of both phases in the composites. Magnetic properties were investigated using a vibrating sample magnetometer (VSM) and ferromagnetic resonance (FMR) measurements at room temperature. Strong magnetoelectric (ME) coupling was demonstrated by an electric field tunable FMR field shift. A large value of converse ME coefficient 109 Oe-cm kV(-1) was observed for NBT/CFO 70/30 composite. Furthermore, these lead-free multiferroic composites exhibiting a large converse magnetoelectric effect at room temperature provide great opportunities for electrostatically tunable devices at microwave frequencies. (C) 2012 American Institute of Physics. [doi:10.1063/1.3679054]