采用同轴反相激励非晶合金/压电复合磁电双单元非线性磁电效应的磁传感器

The magnetic sensor utilizing coaxial anti-phase-modulated nonlinear magnetoelectric effect of amorphous alloy/piezoelectric composite dual-unit

具有高磁导率的非晶合金在低于10Oe磁场激励下就发生饱和磁化,从而非晶合金/压电复合材料在较高幅度、频率为f_(0)f_(0)的交变磁场激励下产生非线性磁电效应,通过解调奇次谐波(f_(0),3f_(0),…)输出,可实现静态/准静态弱磁场测量,且无需另外施加偏置磁场。利用两个同轴配置的FeNiMoSiB/PZT/FeNiMoSiB复合结构单元,设计180°反相磁场激励,并且采用压电双晶片的电连接方式配置两磁电单元压电层输出,从而实现传感器灵敏度倍增和共模噪声抑制。磁电电压信号经差分放大和锁相解调后,得到传感输出信号。测试结果表明:在±100μT线性区范围内,传感器的灵敏度达到2.77×10^(4)μV/μT;对频率为1 Hz磁场的最低探测极限为10 nT。

The nonlinear magnetoelectric(ME) effect occurs under the high-amplitude ac excitation magnetic field in the prototype comprising of a piezoelectric lead zirconate titanate sandwiched between two layers of the amorphous alloy. Due to the nonlinear effect, the composite structure generates odd voltage harmonics modulated to measure the weak DC/AC magnetic field in the absence of a dc bias. The focus of this paper is to present a novel ME senor based on two FeNiMoSiB/PZT/FeNiMoSiB composites utilizing coaxial 180° anti-phase-modulated mode and differential output like the piezoelectric bimorph. In this design, the even voltage harmonics because of frequency doubling effect of magnetostriction is greatly attenuated. The performance of the sensor is enhanced through the proposed manner. The sensitivity of the coxial anti-phase-modulated differential ME dual-unit is 152.4μV/μT which is about two times bigger than that of individual unit. And the limit of detection is 8 nT/√Hz at 1 Hz. Further more, Configured with differential and lock-in amplifier circuits based on AD620 and AD630 respectively, the sensitivity reaches 2.77×10^(4) μV/μT in the linear range of ±100μT. The limit detecition is 10 nT/√Hz at 1 Hz. The small size, light weight and low cost make the nonlinear ME sensor suitable for the dendetection of of magnetic field.