Nonlinear magnetoelectric effects in a composite piezomagnetic–piezoelectric semiconductor structure

In this paper, magnetoelectric effects in a composite piezomagnetic–piezoelectric semiconductor structure with the consideration of nonlinear constitutive relation is studied. On the basis of coupled field theory for composite piezomagnetic–piezoelectric semiconductor, the governing equations are established by considering the nonlinear drift–diffusion theory and Euler’s beam theory. To overcome the difficulties in solving the nonlinear boundary value problem, an iteration procedure is proposed based on the differential quadrature method. The numerical calculation shows the convergence of proposed method is fast, only five iterations can provide enough accuracy. Applying different magnetic fields, it can be found the effects of nonlinear constitutive relation on the electrical field quantities are larger when the composite structure serving in a stronger magnetic field. Comparing to the results from linear theories, the symmetries of all electric field quantities are altered by considering the nonlinear constitutive relation. From the calculated results, it can also be found the differences between linear and nonlinear results are sensitive to the thickness ratio. Importantly, when the thickness ratio changes from zero to one, the predicted magnetoelectric coefficient and carrier production in linear theory are smaller than them in nonlinear theory. Furthermore, the electric field quantities in different material combinations indicate that the nonlinear coupling properties are closely related to the strength of piezoelectric coupling. The conclusions in this paper could be the guidance in designing magnetoelectric devices.