Magnetic-mechanical-electric Coupling Effect Under Control Of Pre-stress In Magnetoelectric Laminate Composite Devices

Magnetoelectric effect (ME) is the one in material an electric field isgenerated by the applied magnetic field, or by an external electric field induced byfield magnetic. The former is called positive magnetoelectric effect (DME), whilethe latter is known as the inverse magnetoelectric effect (CME). As themagnetoelectric effect, more and more attention is attached to magnetic materials.Sensors, actuators, filters, phase shifters, resonators and other devices made ofmagnetoelectric materials have a broad application prospects in the miniaturizationof modern electronic devices, multi-functional development today. Compared withthe particulate magnetic materials, laminated magnetoelectric composites constitutedby magnetostrictive material and piezoelectric ceramics have more practical value insome magnetoelectric items because of their large magnetic-electric conversioneffect, simple production method, and studying the magnetoelectric coupling,especially the magnetoelectric coupling effect, can provides a theoretical basis forthe design of new high-precision and miniaturization devices based onmagnetoelectric laminate.Based on the nonlinear constitutive model of GMM, which is complexlydependent on the bias conditions, this paper establishes a dynamic materialparameters model of Young’s modulus, piezomagnetic coefficient and permeability.By the explicit model, we can effectively predict the variation of the materialconstants of giant magnetostrictive material under the level of pre-stress and biasmagnetic field; in particular, it can be a good description of Eeffect. Then weuse experimental results of piezomagnetic coefficient, magnetic permeability andYoung’s modulus of Terfenol-D and Terfenol-D/polymer respectively to validate themodel in this paper. The comparison shows a good agreement both qualitatively andquantitatively, that verify the model. The explicit model can provide the necessarytheoretical basis for developing high-performance giant magnetostrictive devices(such as actuators, sensors, electronic devices, etc.) by setting reasonable conditions.Then based on the dynamic material constant model of magnetostrictive material,we further analysis the MPM (the magnetostrictive layer/piezoelectric layers/the magnetostrictive layer) layer’s magnetoelectric coupling under low-frequencyandresonant state. First we use the magnetic equivalent circuit method to establish-magnetic-mechanical-electric equivalent circuit of laminated structure, according tothe circuit, we can obtain magnetoelectric coefficient expression, and we can clearlysee the magnetoelectric coefficient has a strong nonlinear relationship with theapplied bias magnetic field, pre-stress and volume ratio of M layer by the expression.Putting the previous dynamic material constants into the magnetoelectric coefficientexpression, we can see the results obtained are in good agreement with theexperimental values, confirming the formula. Then we can predict themagnetoelectric coefficient under different bias field, pre-stress and the volume ratio.It can be seen that there exists an optimal bias magnetic field and the volume ratio.Meanwhile, the smaller the compression pre-stress or the larger tensile pre-stressvalue, the stronger the magnetoelectric coupling effect and it will correspond to thesmaller the bias magnetic field. So we can use the pre-stress to improve the deviceperformance, and reduce the applied additional magnetic coil desired in the device tothe miniaturization.