High magnetoelectric coupling in piezoelectric modified BNT and magnetic NZFO particulate composite

Abstract

Lead-free magnetoelectric (ME) particulate composite comprising piezoelectric 72.5Bi0·5Na0·5TiO3-22.5Bi0·5K0·5TiO3–5BiMg0·5Ti0·5O3 (MBNT) and piezomagnetic Ni0·7Zn0·3Fe2O4 (NZFO) in varying phase fraction, i.e., (1-x)MBNT-xNZFO (x = 0.05–0.30; Δx = 0.05) was prepared by solid state reaction route. Their structural, electrical, magnetic and ME properties were investigated. The high temperature sustainability up to 390 °C and the relaxor behavior was confirmed by their dielectric study. The room temperature dielectric constant (∼1081 at 1 kHz), saturation polarization (∼37.12 μC/cm2) and electro-strain (∼0.22 %) was observed maximum for pure MBNT, which decreases in composites with the induction of non-ferroelectric NZFO content. All composites exhibited magnetic hysteresis behavior where net increase in magnetization was associated with the relative increase in NZFO that possessed a saturation magnetization of 74.52 emu/g. At the optimum phase fraction of composite (i.e., 0.80MBNT-0.20NZFO), giant ME coefficient (∼58.12 mV/cm.Oe at 800 Oe) was observed at low frequency of 10 Hz, which suggest its credibility for energy harvester.