Piezoelectric response of a PZT thin film to magnetic fields from permanent magnet and coil combination

Abstract

In this study, we report the magnetically induced electric field E3 in Pb(Zr0.57Ti0.43)O3 (PZT) thin films, when they are subjected to both dynamic magnetic induction (magnitude Bac at 45 kHz) and static magnetic induction (Bdc) generated by a coil and a single permanent magnet, respectively. It is found that highest sensitivity to Bdc—\( {{\Delta \left| {E_{3} } \right|} \mathord{\left/ {\vphantom {{\Delta \left| {E_{3} } \right|} {\Delta B_{\text{dc}} }}} \right. \kern-0pt} {\Delta B_{\text{dc}} }} \)—is achieved for the thin film with largest effective electrode. This magnetoelectric (ME) effect is interpreted in terms of coupling between eddy current-induced Lorentz forces (stress) in the electrodes of PZT and piezoelectricity. Such coupling was evidenced by convenient modelling of experimental variations of electric field magnitude with both Bac and Bdc induction magnitudes, providing imperfect open circuit condition was considered. Phase angle of E3 versus Bdc could also be modelled. At last, the results show that similar to multilayered piezoelectric-magnetostrictive composite film, a PZT thin film made with a simple manufacturing process can behave as a static or dynamic magnetic field sensor. In this latter case, a large ME voltage coefficient of \( \alpha = {{\left| {E_{3} } \right|} \mathord{\left/ {\vphantom {{\left| {E_{3} } \right|} {B_{\text{ac}} }}} \right. \kern-0pt} {B_{\text{ac}} }} = 3.55\,{\text{V}}/{\text{cm}}\,{\text{Oe}} \) under Bdc = 0.3 T was found. All these results may provide promising low-cost magnetic energy harvesting applications with microsized systems.