Effect of aspect ratio of piezoelectric constituents on the energy harvesting performance of magneto-mechano-electric generators

In this study, we investigate the effect of the aspect ratio (length (L)/width (W)) of piezoelectric constituents on the energy harvesting performance of cantilever-structured magneto-mechano-electric energy generators comprising magnetoelectric composites. 56 Pb(Mg1/3,Nb1/3)O3–10PbZrO3–34PbTiO3 (PMN-PZT) single crystal fiber bundled plates with different aspect ratios (L/W = 0.59, 0.78, 1, 1.25, and 1.6), a magnetostrictive Ni plate and NdFeB permanent magnet proof mass were used to fabricate the magneto-mechano-electric generator. The results of a finite element analysis showed that the output electric potential is strongly dependent on the aspect ratio of PMN-PZT single crystal fiber plates for dual potential-inducing mechanisms, i.e., the magnetic torque (flexural transverse) and magnetic magnetostrictive (in-plane longitudinal) vibrations. However, magnetostrictive vibrations rather than magnetic torque dominate the generated output energy. The experimental results show good agreement with the results of the finite element analysis. The magneto-mechano-electric harvester with a PMN-PZT single crystal fiber aspect ratio of 1.6 shows a ∼440% increment in the root mean square voltage and power and a ∼300% enhancement in the power density measured at a load resistance of 100 kΩ and a magnetic field of 10 Oe.