Multiferroics application: Magnetic controlled piezoelectric transformer

Abstract

Dense lead zirconate titanate (PZT) ceramics is typically used for fabrications of high power piezoelectric devices. In case of lanthanum and iron ions doping into PZT solid solution (PLFZT), material exhibiting both piezoelectric and magnetic properties can be obtained. Among many investigated compositions particularly the Pb0.91(La0.5Fe0.5)0.09(Zr0,65Ti0,35 )0,9775O3, located near the morphotropic boundary, exhibits the highest magnetoelectric effect. This coupling between magnetization and polarization is achieved by the Fe3+ ions addition that sufficiently rise sensitivity to magnetic field without decreasing the dielectric loss coefficient at the same time. Taking advantage of this specific material the piezoelectric transformer (PT) with magnetic feedback was fabricated, which converts an electrical AC input voltage into ultrasonic vibrations and reconverts back to an output as AC voltage proportionally to the magnetic field intensity. In the present study the unipoled radial mode piezoelectric transformers based on PLFZT-type ceramics prepared by hot-press sintering have been investigated. The effect of the magnetic field on the operating properties was measured for piezoelectric transformer operating at the first resonance frequency.