Study On The Influence Of Bias Magnetic Field On Magnetoelectric Effect Of Giant Magnetostrictive/Piezoelectric Composite Material

Magnetoelectric (ME) composite materials have received increasing attention because of its remarkable ME effect. ME composite materials can be used for magnetoelectric transducers, such as magnetic field sensors. The researches show that the ME effect in ME composite materials is closely related to bias magnetic fields. By combining nonlinear constitutive model for giant magnetostrictive material (GMM) with equivalent circuit of laminated materials, this paper analyzes the influence of bias magnetic field on the resonant ME effect of composite material, and compares the theoretical values with experimental results. The main work is as follows:Comparison is made on four kinds of macroscopic phenomenological models for GMM. It is found that the Z-L model is more accurate than other models in simulating nonlinear characteristics of GMM. Dynamic Young's modulus, dynamic piezomagnetic coefficient and dynamic permeability of GMM are derived based on the nonlinear constitutive model for GMM.Based on the piezoelectric, piezomagnetic and dynamic equations, the equivalent circuit of magnetostrictive/elastic/piezoelectric laminate composite is obtained. Because the mechanical loss can not be neglected in the vibration process of the laminate composite, it is necessary to consider it in the equivalent circuit with the introduction of complex parameters. Such equivalent circuit with loss can be used to characterize the laminate composite at resonant frequency. We derive the resonant frequency equation and the ME voltage coefficient expression of the laminate composite.The dynamic Young's modulus and the dynamic piezomagnetic coefficient are substituted in the resonance frequency equation and the ME voltage coefficient expression. Thus the relationship between ME effect and bias magnetic fields can be obtained. It is shown that the bias magnetic field changes the resonant frequency by affecting the dynamic Young's modulus of GMM; the bias magnetic field changes the resonant ME voltage coefficient by affecting both the dynamic Young's modulus and the dynamic piezomagnetic coefficient of GMM.Terfenol-D/beryllium bronze /PZT-5H sample is made. And its magnetoelectric performance is measured under different bias magnetic fields. By comparing the theoretical analysis with experimental results, it is showed that:â‘ The resonant frequency of the composite firstly decreases, then increases as the bias magnetic field increases;â‘¡The resonant ME voltage coefficient of the composite increases firstly, then decreases as the bias magnetic field increases;â‘¢There is an optimal bias magnetic field at which the resonant ME voltage coefficient reaches its maximum.