Magneto-mechanical coupling characteristic analysis of a magnetic energy nanoharvester with surface effect

In the current work, a nonlinear magnetoelectric (ME) coupling model is developed to investigate the working performance of a magnetic energy nanoharvester, which is composed of a magneto-electro-elastic (MEE) laminated cylindrical nanoshell array when the circuit is connected either in series or in parallel. The analytical results indicate that the performance of nanoharvester exhibits obvious size-dependent phenomenon, including the resonant frequency, output electrical power density, efficiency and so forth, which is only attributed to the surface effect. Based on this, a critical thickness, distinguishing micro-scale from macro-scale, is proposed, below which the size-dependent effect must be included during mechanical analysis. On the other hand, it is demonstrated that the output electrical power, as an important performance index, can be improved evidently and tuned artificially via the pre-stress and matched magnetic field, which may provide us opportunity to control the harvester in nano-scale. The current work is essential and crucial for the physical phenomenon explanations and experimental design of the MEE nanodevices, especially in the extremely complex magnetic and pre-stress field environments.