Electric field tunable magnetic properties of lead-free Na0.5Bi0.5TiO3/CoFe2O4 multiferroic composites

Lead-free multiferroic particulate composites of Na0.5Bi0.5TiO3 (NBT) and CoFe2O4 (CFO) have been synthesized by solid-state sintering method. A systematic study of structural, magnetic and magnetoelectric (ME) properties is undertaken. Structural and morphology studies carried out by x-ray diffraction and field emission scanning electron microscopy indicate formation of single phase for parent phases and presence of both phases in the composites. Magnetic properties are investigated using vibrating sample magnetometer and ferromagnetic resonance (FMR) measurements at room temperature. Strong ME coupling is demonstrated in NBT-CFO 70-30 mol% composite by an electrostatically tunable FMR field shift up to 428 Oe (at E = 3.9 kV/cm), which increases to a large value of 640 Oe at E = 6.8 kV/cm. Furthermore, these lead-free multiferroic composites exhibiting electrostatically induced magnetic resonance field at microwave frequencies provide great opportunities for electric field tunable microwave devices.