Electrically modulated magnetoelectric sensors
Electrically modulated magnetoelectric sensors
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DOI：
10.1063/1.4948470
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发表时间：
2016-05-02
影响因子：
4
通讯作者：
Quandt, E.
中科院分区：
文献类型：
--
作者：
Hayes, P.;Salzer, S.;Quandt, E.
如果利用机械共振(通常是几百赫兹到几千赫)，磁电薄膜复合材料已经证明了它们检测亚PT磁场的潜力。在低频(1-100赫兹)下，磁场感应频率转换利用磁致伸缩曲线的非线性特性，使宽带测量具有共振增强的灵敏度。然而，利用频率接近机械共振的磁场进行调制会导致许多缺点，例如传感器的尺寸和能量消耗以及传感器阵列中的潜在串扰。在这项工作中，我们论证了磁电式传感器的电频率转换的可行性，它将克服磁频率转换的缺点。这种磁电式传感器由三层功能层组成：不加偏磁、具有高压磁系数的交换偏置磁致伸缩多层膜、非线性压电致动层和线性压电传感层。在这种方法中，低频磁信号被移到传感器的机械谐振中，而电调制频率被选择为谐振和信号频率的差或和。使用这种电子频率转换，对低频信号显示了低nT/赫兹(1/2)范围内的检测极限。由AIP出版公司出版。
Magnetoelectric thin film composites have demonstrated their potential to detect sub-pT magnetic fields if mechanical resonances (typically few hundred Hz to a few kHz) are utilized. At low frequencies (1-100 Hz), magnetic field-induced frequency conversion has enabled wideband measurements with resonance-enhanced sensitivities by using the nonlinear characteristics of the magnetostriction curve. Nevertheless, the modulation with a magnetic field with a frequency close to the mechanical resonance results in a number of drawbacks, which are, e.g., size and energy consumption of the sensor as well as potential crosstalk in sensor arrays. In this work, we demonstrate the feasibility of an electric frequency conversion of a magnetoelectric sensor which would overcome the drawbacks of magnetic frequency conversion. This magnetoelectric sensor consists of three functional layers: an exchange biased magnetostrictive multilayer showing a high piezomagnetic coefficient without applying a magnetic bias field, a non-linear piezoelectric actuation layer and a linear piezoelectric sensing layer. In this approach, the low frequency magnetic signal is shifted into the mechanical resonance of the sensor, while the electric modulation frequency is chosen to be either the difference or the sum of the resonance and the signal frequency. Using this electric frequency conversion, a limit of detection in the low nT/Hz(1/2) range was shown for signals of low frequency. Published by AIP Publishing.