Studies on lead-free multiferroic magnetoelectric composites

Lead-free multiferroic magnetoelectric composites consisting of ferrimagnetic Ni_0.93Co_0.02Mn_0.05Fe_1.95O₄ (NMF) and ferroelectric Na_0.5Bi_0.5TiO₃ (NBT) phases were synthesized by the solid-state sintering method. The presence of constituent phases in composites was confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). A systematic study of dc conductivity as a function of temperature (RT −450 °C) revealed that the conduction is due to small polarons. The effect of constituent phase variation on the dielectric constant and piezoelectric strength (d₃₃) was examined. The composites exhibited typical magnetic hysteresis (M–H) loops at room temperature. Furthermore, magnetoelectric (ME) output was evaluated as a function of applied magnetic field, which is a product property of the constituent phases. The compound 50% NMF–50%NBT is a new lead-free magnetoelectric composite with 155 μV/cm ME output, which may have potential applications.