Shaped Magnetic Composite Magnetic Resonance Frequency Shift Caused By Research

Magnetoelectric (ME) effects of magnetoelectric composites material, due to reverse piezomagnetic effect in the magnetostrictive phase,the magnetostriction gives rise to mechanical stresses that are passed into the piezoelectric phase, which is the product property derived from the mechanical coupling in magnetoelectric composites material. ME voltage coefficient are considered to be the important indicators of magnetic-electric conversion. In these studies, two magnetic fields are needed, a bias field H and an ac field δH. both are arranged to be parallel to each other.In fact, a single dc magnetic field can also give rise to a changing of the stress and strain in, which belongs to the piezoelectric phase. Therefore the piezoelectric resonance frequency and the dielectric permittivity of the piezoelectric phase is possibly affected by the applied single dc magnetic field,so the degree of polarization for the piezoelectric phases can been controled by magnetic fields. In the end, there appear a resonant frequency shift which we are interested in. However the traditional layered structures of piezoelectric and magnetostrictive phases are in a horizontally layered plate shape and coupled through shear stresses, which is maybe responsible for the weak interfacial mechanical coupling. We choose the strip-ring heterostructures where the coupling is through normal stresses to study the shift of the resonance frequency with the enhanced magnetoelectric properties.There have many factors affect the mechanical resonant frequency of the composite materials, and it’s necessary to set up a model to explain the phenomenon.In this study,we choose the strip-ring heterostructures to study the shift of the resonance frequency. The PZT-strip/NZFO-ring are choosed respectively, experimental research the relationship of capacitance and resonance frequency under a single dc magnetic field. Through the magnetostriction and piezoelectric constitutive equation, we puts forward a kind of magnetoelectric coupling theory model in the strip-ring heterostructures, and deduced the relationship between the capacitance, resonance frequency, magnetic field and material parameters. We apply it for the case of PZT-strip/NZFO-ring and PZT-strip/TDF-ring composites.It were simulated for The relationship between the capacitance,frequency and coupling coefficient in the strip-ring strutures,the results are consistent very well with the experimental value. With the applying of the single dc field, the strip-ring composite structure shows promising properties for the detection of magnetic filed.