Magnetic Composites And Device Design

Magnetoelectric materials are a class of novel multi-functional materials, which have many potential applications. They not only have ferroelectric and magnetic properties, but also the magnetoelectric effect produced from coupling interaction between electric and magnetic orders. Based on our previous researches, we performed deep experimental investigations on a kind of new PZT/Terfenol-D composite consisting of piezoelectric ceramics and magnetostrictive alloy.Firstly, we researched the double layer PZT/Terfenol-D composite material. The magnetoelectric effect is various with bias magnetic fields and frequency. We found they have relative fine magnetoelectric properties.Secondly, we prepared a sort of structure of magnetoelectric composites with PMNT/Terfenol-D/PMNT sandwiched structure and studied the electric-field-induced magnetization. We found that the resonance of composite, the magnetoelectric coefficient and the phase shift vary with the frequency. The magnetoelectric coefficient of the sandwiched structure reached two times more than that of the double layer composite.Thirdly, we researched the symmetrical and asymmetrical structure for the triple layer and double layer of PZT/Terfenol-D magnetoelectric materials. We found the magnetic-field-induced electric polarization (MIE) and the electric-field-induced magnetization (EIM) were strengthened near the resonance frequency. The resonant peak shifts with the bias magnetic field, which depends on sonic the variety of Tefenol-D in the magnetic field. Through the two different electrical circuit connections, we found the magnetoelectric property is relative to the thickness ratio of PZT and Terfenol-D.Finally, we explored the magnetoelectric models by using the magnetoelectric composite materials. And we made a magnetoelectric device by using a Rosen-type piezoelectric transform and Terfenol-D alloy. We discussed about the variation of EIM when Rosen piezoelectric transform changes. In addition, we got that this magnetoelectric coefficient increased a lot, although the magnetoelectric properties of this structure still have to be further increase, such as by optimizing the parameter of this composite material structure.