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Enhanced Giant Magnetoelectric Effect in Laminate Composites of FeCuNbSiB/FeNi/PZT
Yumei Wen,Dong Wang,Ping Li 한국자기학회 2011 Journal of Magnetics Vol.16 No.4
A novel laminate composite of FeCuNbSiB/FeNi /PZT is proposed, where FeCuNbSiB has a permeability of around 100000, which is much larger than that of FeNi. The high-permeability FeCuNbSiB was laminated with piezomagnetic FeNi rather than attached to its ends. It is expected that the effect produced by the high permeability will act on the whole of the piezomagnetic layer. While a FeNi layer was laminated with a FeCuNbSiB layer, the strong demagnetization produced by the latter was expected to be imposed on the FeNi layer as well as the applied fields. The distribution of applied fields was altered by the high-permeability material (both bias and ac field) and the field variation positively contributed to the ME effect in piezomagnetic/piezoelectric composites. Thus the ME voltage coefficient along with the field sensitivity were improved.
Leixiang Bian,Yumei Wen,Ping Li,Qiuling Gao,Xianxue Liu 한국자기학회 2009 Journal of Magnetics Vol.14 No.2
The dynamic magneto-mechanical behaviors in a type of iron-nickel-based ferromagnetic alloy with constant elasticity were investigated as a function of both the DC bias magnetic field (Hdc) and the frequency. The rectangular plate-like samples were excited to vibrate at a half-wavelength, longitudinal resonance by an AC magnetic field superimposed with various Hdc. The experimental results found that the strain coefficient at resonance reached 819.34 ㎚/A and the effective mechanical quality factor (Qm) was greater than 2000. The ratio of the maximum variation of the Young’s modulus over Hdc to the value of the Young’s modulus at a zero bias field was only ~0.83‰ because of the so-called constant elasticity. The resonant strain coefficients and Qm are strongly dependent on Hdc, which indicates a promising potential for use in DC and quasistatic magnetic field sensing.
The Dumb-bell Shaped Magnetostrictive/Piezoelectric Transducer
Jianzhong Li,Yumei Wen,Ping Li 한국자기학회 2011 Journal of Magnetics Vol.16 No.4
Traditional magnetostrictive/piezoelectric laminate composites are generally in the regular geometries such as rectangles or disks. To explore properties of the irregular geometry magnetostrictive/piezoelectric transducer in the fundamental resonant frequency, a step dumb-bell shaped Magnetoelectric (ME) transducer is presented in this study. Both analytical and experimental investigations are carried out for the dumb-bell shaped transducer in the fundamental frequency. Comparing with the traditional rectangular transducer, the theory shows the resonant frequency of dumb-bell shaped transducer is reduced 31%, and the experiment gives the result of that is 37% which is independent of dc magnetic fields. The ratio of magnetoelectric voltage coefficient (MEVC) between the dumb-bell shaped and rectangular shaped transducers in theory is 66% comparing with that of in experiment is varying from 140% to 33% when the dc field is increased from 0 Oe to 118 Oe.
Zhiyi Wu,Yumei Wen,Ping Li,Jin Yang,Xianzhi Dai 한국자기학회 2011 Journal of Magnetics Vol.16 No.2
The magnetostrictive material is magnetized in magnetic field and produces a nonuniform demagnetizing field inside and outside it. The demagnetization is decided by the permeability of magnetostrictive material and its size. The magnetoelectric performances are determined by the synthesis of the applied and demagnetizing fields. An analytical model is proposed to predict the magnetoelectric voltage coefficient (MEVC) of magnetostrictive/piezoelectric laminate composite using equivalent circuit method, in which the nonuniform demagnetizing field is taken into account. The theoretical and experimental results indicate that the MEVC is positively connected with the permeability and the piezomagnetic coefficient of magnetostrictive material. To obtain the maximum MEVC, both the permeability and the piezomagnetic coefficient of magnetostrictive material should be taken into account in selecting the suitable magnetostrictive material.
A New Vibration Energy Harvester Using Magnetoelectric Transducer
Jin Yang,Yumei Wen,Ping Li,Xianzhi Dai,Ming Li 한국자기학회 2011 Journal of Magnetics Vol.16 No.2
Magnetoelectric (ME) transducers were originally intended for magnetic field sensors but have recently been used in vibration energy harvesting. In this paper, a new broadband vibration energy harvester has been designed and fabricated to be efficiently applicable over a range of source frequencies, which consists of two cantilever beams, two magnetoelectric (ME) transducers and a magnetic circuit. The effects of the structure parameters, such as the non-linear magnetic forces of the ME transducers and the magnetic field distribution of the magnetic circuit, are analyzed for achieving the optimal vibration energy harvesting performances. A prototype is fabricated and tested, and the experimental results on the performances show that the harvester has bandwidths of 5.6 ㎐, and a maximum power of 0.25 ㎽ under an acceleration of 0.2 g (with g = 9.8 ㎳²).
A High-sensitivity Passive Magnetic Transducer Based on PZT Plates and a Fe-Ni Fork Substrate
Ping Li,Yumei Wen,Chaobo Jia,Xinshen Li 한국자기학회 2011 Journal of Magnetics Vol.16 No.3
This paper proposes a magnetoelectric (ME) composite transducer structure consisting of a magnetostrictive Htype Fe-Ni fork substrate and piezoelectric PZT plates. The fork composite structure has a higher ME voltage coefficient compared to other ME composite structures due to the higher quality (Q) factor. The ME sensitivity of the fork structure reaches 12 V/Oe (i.e., 150 V/㎝ Oe). The fork composite with two PZT plates electrically connected in series exhibits over 5 times higher ME voltage coefficient than the output of the rectangle structure in the same size. The experiment shows the composite of a Fe-Ni fork substrate and PZT plates has a significantly enhanced ME voltage coefficient and a higher ME sensitivity relative to the prior sandwiched composite laminates. By the use of a lock-in amplifier with 10 ㎵ resolution, this transducer can detect a weak magnetic field of less than 10?¹² T. This transducer can also be designed for a magnetoelectric energy harvester due to its passive high-efficiency ME energy conversion.