The Simulation Of Converse Magnetoelectric Effect And Design Of Multiferroic Composite Material

Multiferroic materials composed of ferromagnetic materials and ferroelectric materials have strong magnetoelectric conversion ability,among which the converse magnetoelectric(CME)effect can convert electrical signals into magnetic signals.In recent years,it has been widely used in sensing,microwave,spin and storage and other fields.With the progress of experimental exploration,theoretical calculation and device design,the research on CME effect is also deepening.Aiming at the laminated structure of ferromagnetic/ferroelectric composite materials,and based on the finite element simulation modeling,this paper studies the nonlinear CME effect under the multi-physical field environment,and further explores the multiferroic antenna based on multiferroic heterostructures film.The specific research content is as follows:Firstly,a nonlinear Finite Element Method(FEM)simulation based on COMSOL Multiphysics is developed to model the response of CME effect in the magnetoelectric(ME)composite of piezoelectric and magnetostrictive materials.In this model,the nonlinear magnetostrictive constitutive relationship is considered.The nonlinear parameters estimation is performed by integrating the MATLAB function with COMSOL via the LiveLink for MATLAB tool.The results of the numerical simulations for CME coefficients have been presented and compared with the experiment results which shows a good agreement.The non-uniform magnetic field and displacement distributions are present.The CME mechanism for the nonlinear response are analyzed.Secondly,the electric tuning behavior of CME effect is predicted,which demonstrats complex mechanism between the bias voltage induced strain-mediated effect and the converse magnetostrictive effect.Additionally,the CME coefficient of thin film ME composites is investigated for different conditions,including the material properties of magnetostrictive phase and the mechanical boundary conditions.It has been revealed that:(1)Besides the magnetostriction coefficient,the initial magnetic susceptib ility provides another degree to enhancing the CME effect and decreasing the optimum bias magnetic field;(2)The mechanically clamped boundary condition can enhance the CME effect approximately ten times as compared with the traction-free case.Finally,the working principle of multiferroic antenna is discussed,and the theoretical mechanism of multiferroic antenna which is different from traditional antenna is analyzed.Taking FeGaB/AlN multiferroic heterostructures as the research object,and considering the nonlinear constitutions and(35)E effect of magnetostrictive materials,the three-dimensional finite element model of multiferroic antenna is established by means of COMSOL.The stress and electric field distribution of the antenna in the frequency domain and the radiation pattern in the far field domain are analysed.In this thesis,based on simulation calculation,the CME effect is studied in theory and device design.The content provides a good supplement for the existing research on the CME effect,and in the meanwhile it gives a certain reference for the follow-up research in this field.