Global and local flexotronic effects induced by external magnetic fields in warping of a semiconducting composite fiber

The flexotronic effects induced by external magnetic fields in warping of a composite fiber consists of a flexoelectric semiconductor (nonpiezoelectric) and two piezomagnetic coated layers are investigated in this work. The macroscopic piezomagnetic and flexoelectric theories are employed. A one-dimensional model is derived from the three-dimensional framework, in which one zeroth-order electric potential, one zeroth-order concentration perturbation of holes and three deformation modes including extension, thickness-stretch and symmetric shear are considered. The current model gives a magnetically controlled flexoelectric field and charge redistribution through a warping deformation, whose design of such a composite is firstly proposed. The composite fiber under both global and local magnetic fields are respectively studied. Based on the numerical results, the external magnetic fields can be utilized to tune or control the warping deformation of the composite fiber. Numerical results show that various distributions of charge carriers along the axial direction arising from flexoelectricity can be manipulated by different magnetic fields in warping of the current composite fiber. In addition, the maximum value of the charge accumulation can be attained by tailoring the thickness ratio of the piezomagnetic and flexoelectric semiconductor layers. This paper provides a new idea for designing flexotronic devices.