Magnetoelectric Coupling in Metglas/BaTiO3/Metglas Lead-Free Magnetoelectric Composites

We report the magnetoelectric (ME) coupling in ME composites composed of NiFe2O4 (NFO) or metglas as magnetostrictive phases and BaTiO3 (BTO) as piezoelectric phase, targeting lead free magetnic field sensors. NFO and BTO phases were synthesized by solid state sintering method and further characterized by using XRD and FESEM techniques. The P-E hysteresis curve shows good ferroelectric behavior with saturation polarization of Ps = 15.87 C/cm2 and coercive electric field of 130 kV/cm. The ME response was characterized as a function of dc magnetic field at a fixed frequency. The transverse ME voltage coefficient, αME31 shows 2 times larger magnitude than that of longitudinal ME voltage coefficient, αME31. The maximum αME31 of 37 mV/cm•Oe (@Hdc = 250 Oe) is observed for NFO/BTO/NFO ME composites with thickness ratio of tm/tp = 1.0. The ME coupling is further enhanced by replacing NFO layers by highly magnetostrictive metglas layers. Metglas/BTO/metglas laminates show large αME31 value of 81 mV/cm•Oe at relatively lower Hdc of 145 Oe. The present laminates can offer promising opportunities of engineering environmental friendly ME laminate for applications in ME devices such as energy harvester and magnetic field sensors.