Output characteristics in Fe–Pd/PZT/Fe–Pd magneto-electric composites with Fe–Pd thick layer

Magneto-electric (ME) characteristics of the ferromagnetic/ferroelectric Fe70Pd30/PZT/Fe70Pd30 thin composites were investigated. The ME composites composed of the ferroelectric PZT phase (center layer, t: 260 μm) and the ferromagnetic, magnetostrictive Fe70Pd30 phase (t: 30–90 μm) glued on both the surfaces of PZT were fabricated. The rapidly solidified Fe70Pd30 ribbon mainly consists of fct martensitic phase with a large magnetostriction and fcc austenite (parent) phase. According to the DC bias magnetic field dependency of the output ME voltage (VME) at an AC magnetic field of 1.0 Oe with an operation frequency of 1 kHz for the composites, the increasing in thickness of magnetostrictive layers showed remarkable improvement of VME values. For the composite with 90 μm Fe–Pd layers, maximum VME value of 13.9 mV was obtained at 60 Oe of the DC field, which is about two times higher than that of the composite with 30 μm Fe–Pd layers. Additionally the VME value of the serial circuit was monotonically enhanced by the serial circuit connection, and the composites exhibited a very large peak at a resonant frequency of 61–68 kHz.