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 E ₃ in Pb(Zr_0.57Ti_0.43)O₃ (PZT) thin films, when they are subjected to both dynamic magnetic induction (magnitude B _ac at 45 kHz) and static magnetic induction (B _dc) generated by a coil and a single permanent magnet, respectively. It is found that highest sensitivity to B _dc—${{\Delta \left| {E_{3} } \right|} \mathord{\left/ {\vphantom {{\Delta \left| {E_{3} } \right|} {\Delta B_{\text{dc}} }}} \right. \kern-0pt} {\Delta B_{\text{dc}} }}$—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 B _ac and B _dc induction magnitudes, providing imperfect open circuit condition was considered. Phase angle of E ₃ versus B _dc 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 B _dc = 0.3 T was found. All these results may provide promising low-cost magnetic energy harvesting applications with microsized systems.