Commercial piezoelectric unimorph diaphragm as a magnetic energy harvester

A magnetoelectric coupling in a low-cost and commercially available piezoelectric unimorph diaphragm is demonstrated by measuring magnetically induced AC voltage from the sample. Such a magnetoelectric effect could be achieved only because of the combination of magnetic forces within the electrodes and piezoelectric effect, without any magnetic constituent. Harvested magnetic power density across an optimal resistive load is found to be 0.12 mW/Oe.cm3 at the bending mode resonance frequency. The proposed transduction mechanism opens new and simple ways for producing electricity from stray magnetic fields.