Sreenivasulu Gollapudi, Qu Peng, Petrov Vladimir, Qu Hongwei, Srinivasan Gopalan
Physics Department, Oakland University, Rochester, MI 48309, USA.
Electrical and Computer Engineering Department, Oakland University, Rochester, MI 48309, USA.
Sensors (Basel). 2016 Feb 20;16(2):262. doi: 10.3390/s16020262.
Multiferroic composites with ferromagnetic and ferroelectric phases have been studied in recent years for use as sensors of AC and DC magnetic fields. Their operation is based on magneto-electric (ME) coupling between the electric and magnetic subsystems and is mediated by mechanical strain. Such sensors for AC magnetic fields require a bias magnetic field to achieve pT-sensitivity. Novel magnetic sensors with a permanent magnet proof mass, either on a ferroelectric bimorph or a ferromagnetic-ferroelectric composite, are discussed. In both types, the interaction between the applied AC magnetic field and remnant magnetization of the magnet results in a mechanical strain and a voltage response in the ferroelectric. Our studies have been performed on sensors with a Nd-Fe-B permanent magnet proof mass on (i) a bimorph of oppositely-poled lead zirconate titanate (PZT) platelets and (ii) a layered multiferroic composite of PZT-Metglas-Ni. The sensors have been characterized in terms of sensitivity and equivalent magnetic noise N. Noise N in both type of sensors is on the order of 200 pT/√Hz at 1 Hz, a factor of 10 improvement compared to multiferroic sensors without a proof mass. When the AC magnetic field is applied at the bending resonance for the bimorph, the measured N ≈ 700 pT/√Hz. We discuss models based on magneto-electro-mechanical coupling at low frequency and bending resonance in the sensors and theoretical estimates of ME voltage coefficients are in very good agreement with the data.
近年来，具有铁磁相和铁电相的多铁性复合材料被研究用作交流和直流磁场传感器。它们的工作基于电磁子系统之间的磁电（ME）耦合，并由机械应变介导。这种用于交流磁场的传感器需要一个偏置磁场来实现皮特斯拉（pT）灵敏度。本文讨论了一种新型磁传感器，该传感器在铁电双压电晶片或铁磁 - 铁电复合材料上带有永磁质量块。在这两种类型中，施加的交流磁场与磁体的剩余磁化之间的相互作用会导致机械应变和铁电体中的电压响应。我们对以下两种传感器进行了研究：（i）一种由极性相反的锆钛酸铅（PZT）薄片组成的双压电晶片，其上带有钕铁硼（Nd-Fe-B）永磁质量块；（ii）一种PZT - 金属玻璃 - 镍的层状多铁性复合材料。已根据灵敏度和等效磁噪声N对这些传感器进行了表征。两种类型传感器的噪声N在1Hz时约为200 pT/√Hz，与没有质量块的多铁性传感器相比，有10倍的改善。当在双压电晶片的弯曲共振频率下施加交流磁场时，测得的N≈700 pT/√Hz。我们讨论了基于传感器低频下的磁 - 电 - 机械耦合和弯曲共振的模型，并且磁电电压系数的理论估计与数据非常吻合。
