Converse magnetoelectric effect in three-phase composites of piezoceramic, metal cap, and magnet

We report experimentally and theoretically the converse magnetoelectric (CME) effect in a three-phase piezoceramic-metal-cap-magnet composite made by sandwiching a thickness-polarized Pb (Zrx Ti1-x) O3 (PZT) disk between two truncated conical brass caps and two thickness-magnetized SmCo disks. The reported CME effect originates from the product of the converse piezoelectric effect in the PZT disk, the mechanical transformation/amplification effect in the brass caps, and the magnetic induction effect in the SmCo disks. The composite exhibits a large CME coefficient (αB) in excess of 2 mGV with a flat response in the broad frequency range of 0.1-100 kHz. The measured magnetic flux density shows an extremely linear relationship to the applied voltage with amplitude varying from 10 to 100 V over a wide range of detection distance of 0.7-6.5 mm. This electromechanomagnetically coupled effect enables applications of the composite in coil-free magnetic flux control devices, featuring smaller Joule heating loss, wider operational bandwidth, and greater property-tailorable flexibility compared to conventional electromagnet-based devices.