Magnetically induced charge redistribution in the bending of a composite beam with flexoelectric semiconductor and piezomagnetic dielectric layers

Abstract

We study electromechanical fields in a thin composite beam of a flexoelectric semiconductor layer sandwiched between two piezomagnetic dielectric layers induced by an applied magnetic field. The macroscopic theory of piezomagnetics and flexoelectric semiconductors is used. A one-dimensional model is derived from the three-dimensional equations. Responses under static and time-harmonic magnetic fields are obtained analytically from the model. Results show magnetically induced bending deformation and redistribution or motion of charge carriers toward the top and bottom of the beam through combined piezomagnetic and flexoelectric couplings. A coupling coefficient depending on the physical and geometric parameters of the structure is introduced to characterize the strength of the effect. The coupling coefficient assumes a maximum for a specific thickness ratio of the piezomagnetic and semiconductor layers. The results are fundamental to the emerging field of flexoelectronics when magnetic fields are involved.