Nonlinear magneto-mechanical-thermo coupling characteristic analysis for transport behaviors of carriers in composite multiferroic piezoelectric semiconductor nanoplates with surface effect

In this paper,to better reveal the surface effect and the screening effect as well as the nonlinear multi-field coupling characteristic of the multifunctional piezoelectric semiconductor(PS)nanodevice,and to further improve its working performance,a magneto-mechanical-thermo coupling theoretical model is theoretically established for the extensional analysis of a three-layered magneto-electro-semiconductor coupling laminated nanoplate with the surface effect.Next,by using the current theoretical model,some numerical analyses and discussion about the surface effect,the corresponding critical thickness of the nanoplate,and the distributions of the physical fields(including the electron concentration perturbation,the electric potential,the electric field,the average electric displacement,the effective polarization charge density,and the total charge density)under different initial state electron concentrations,as well as their active manipulation via some external magnetic field,pre-stress,and temperature stimuli,are performed.Utilizing the nonlinear multi-field coupling effect induced by inevitable external stimuli in the device operating environment,this paper not only provides theoretical support for understanding the size-dependent tuning/controlling of carrier transport as well as its screening effect,but also assists the design of a series of multiferroic PS nanodevices.

Effect of Interface Area on Nonlinear Magnetoelectric Resonance Response of Layered Multiferroic Composite Ring

Multiferroic composite structures are widely used in sensing,driving and communication.The study of their magnetoelectric(ME)behavior under various excitations is crucial.This study investigates the nonlinear ME influence of a multilayer composite ring structure consisting of Terfenol-D(TD)magnetostrictive and lead zirconate titanate(PZT)piezoelectric rings utilizing a multiphysics field modeling framework based on the fully coupled finite element method.The ME coupling coefficient of the PZT/TD concentric composite ring is predicted using the linear piezoelectric constitutive model and the nonlinear magnetostrictive constitutive model,which is congruent to the experimental data.The effect of the interface area of a trilayered structure on the coupling performance at the resonant frequency is investigated,considering the magnitude and frequency of the magnetic field and keeping the material ratio constant.The ME coupling coefficient of a trilayered structure is larger than that of a bilayered structure with the same material ratio,and the maximum ME coupling coefficient of a trilayered structure increases nonlinearly with the increase in the interface area.At the resonant frequency,the structure's ME coupling performance is considerably improved.An optimization technique based on structural geometric design and magnetic field control is presented to optimize the ME coupling coefficient.

Magnetoelectroelastic fields in rotating multiferroic composite cylindrical structures

An analytical solution is obtained for a rotating multiferroic composite hollow cylinder made of radially polarized piezoelectric and piezomagnetic materials. Both the number of layers and the stacking sequence of the composite cylinder can be arbitrary. General mechanical, electric and magnetic boundary conditions can be applied at both the inner and outer cylindrical surfaces. The state space method is employed so that only a 2×2 matrix is involved in the whole solving procedure. In the nu-merical experiments, the distributions of elastic, electric as well as magnetic fields in an internally pressurized rotating BaTiO3/CoFe2O4 composite hollow cylinder subjected to different boundary conditions are presented graphically. The results clearly show that the stress fields in a multiferroic composite cylinder are controllable.