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

Abstract

We report the magnetoelectric (ME) coupling in ME composites composed of NiFe 2 O 4 (NFO) or metglas as magnetostrictive phases and BaTiO 3 (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 P s = 15.87 C/cm 2 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, α ME31 . The maximum α ME31 of 37 mV/cm • Oe (@ H dc = 250 Oe) is observed for NFO/BTO/NFO ME composites with thickness ratio of t m / t p = 1.0. The ME coupling is further enhanced by replacing NFO layers by highly magnetostrictive metglas layers. Metglas/BTO/metglas laminates show large α ME31 value of 81 mV/cm • Oe at relatively lower H dc 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.