A Magentoelectric Coefficient Measurement System with a Free-Stress Sample Holder

With less extra stress on the testing sample, a free-stress sample holder was designed to place the sample horizontally. With the free-stress sample holder, a magnetoelectric (ME) coefficient measurement system was developed based on dynamic method. This measurement system has the hardware part and the software part, integrated by the DC magnetic field generation module, the AC magnetic field generation module, the induced ME voltage detecting module and PC software module. Then, a sample of Terfenol-D/PZT/Terfenol-D trilayer was designed and fabricated, and the relationships of its ME coefficient influenced by the DC magnetic field and the frequency of the AC magnetic field were tested using the measurement system. And the results showed that the free-stress sample holder was proven to improve the accuracy of the measurement system by less stress interference.

Influences of the Shape of Magnetic Material on the Magnetoelectric Properties of the PZT/Metglas Composite

In this paper,the influences of the shape of magnetic material on the magnetoelectric（ME）properties of PZT/Metglas magnetoelectric（ME）composites have been investigated.The results indicate that,with the decrease of the waist length（L w）of the dumbbell-shaped Metglas,the magnetic flux density in the center region and ME coefficients（αME）of the composites increase,while the optimal bias magnetic field H dc decreases on the contrary.In an AC magnetic field of 1 k Hz,the maximumαME（αMax）of the composite with L w=20 mm exhibits 1.3 times larger than that of the one with L w=50 mm,and the optimal H dc deceases by 15%.At the resonant frequencies of each composites,αMax is enhanced by1.3 times as L w decreases from 50 to 20 mm.The simulation made by Comsol Multiphysics and the theoretical analysis based on an equivalent magnetic circuit confirm the experimental results.

Magnetoelectric Properties of Piezoelectric—Piezomagnetic Composites with Elliptical Nanofibers

Based on the surface/interface theory,the effective magnetoelectric(ME)properties of piezoelectric(PE)-piezomagnetic(PM)composites with elliptical nanofibers are investigated analytically.Using the complex function theory,conformal mapping and the Mori-Tanaka mean-field method,the solutions of magneto-electro-elastic(MEE)fields are obtained,which satisfy both the interface and the single-valued conditions.The closed-form expression of the ME coefficient of the composites shows that the effect of ME coefficient is related to the interface parameters,elliptical aspect ratio,material properties of both fiber and matrix and the fiber volume fraction.Numerical calculation shows that by properly selecting some of these parameters,the effective ME coefficient could be substantially enhanced.

The theory of direct magnetoelectric effect in the bilayer system of ferromagnetic–piezoelectric

The theory of direct magnetoelectric(ME)effect in a bilayer of ferromagnetic and piezoelectric is developed taking into account nonuniform distribution of electrical field on a piezoelectric layer thickness.The simultaneous solution of the motion equations for piezoelectric and ferromagnetic mediums allowed to numerically and analytically calculate the dependence of natural mechanical oscillation on structure parameters and to determine the dependence of ME effect coefficient on frequency of the variable magnetic field.

Enhancement of Magnetoelectric Properties in A Surface-Mount Magnetoelectric Device

The fabrication and properties of a novel double layered surface-mount magnetoelectric（ME） device are investigated and reported. This ME device is made up of two opposite polarized piezoelectric PZT slices bonded on the same side of a magnetostrictive material Metglas, forming a novel two PZT in-series device. ME voltage obtained from the two PZT in-series is obviously higher than that of single PZT in a magnetic field with certain value. The ME voltage coefficient（αV） of the surface-mount ME device is significantly enhanced by adjusting the thickness of Metglas： 1） At a frequency of 1 k Hz, αV of this device increases with the layer number of Metglas increased, and the maximum value of αV is about 4.25 times than the minimum; 2） At a frequency of 5 k Hz, the maximum value of αV is 458 mV /Oe, which derives from the ME device with three layers Metglas. This novel design provides an effective way to manufacture miniature and high sensitive ME devices, which makes it possible to apply ME device into integrated circuit（IC）.