【摘要】 采用磁致伸缩薄膜FeGa作为敏感材料，优化设计了一种新型高灵敏声表面波(SAW)电流传感器。以中心频率150 MHz的延迟线型SAW器件作为传感元，利用射频(RF)磁控溅射法在其表面SAW传播路径上沉积FeGa磁性薄膜，由此构建SAW电流传感器件。将研制的传感器件接入由放大器及混频器组成的振荡电路中，通过与未镀膜参考器件进行差分，其输出信号用作传感信号。在电磁场作用下，FeGa薄膜产生的磁致伸缩效应引起SAW传播速度的改变，最终以相应的差分振荡频率偏移来评估施加的电流值。为进一步提升传感器性能，通过控制不同的溅射功率及退火热处理等制备工艺来确定优化的制备条件。实验结果表明，当FeGa薄膜厚度为500 nm,溅射功率为100 W,退火热处理温度为300℃时，所研制的电流传感器线性度及重复性良好，灵敏度较高(24.67 kHz/A)。更多还原

【Abstract】 Using the FeGa magnetostrictive film as the sensitive material, a surface acoustic wave(SAW) current sensor with high sensitivity is designed and optimized. It is fabricated by using a SAW delay line with a center frequency of 150 MHz as the sensing element, and the FeGa thin film is deposited on the surface of the SAW propagation path of the delay line using radio frequency(RF) magnetically controlled sputtering method. The developed sensor is connected to an oscillation circuit composed of an amplifier and a mixer, and the output signal is used as a sensing signal by making a difference with the uncoated reference device. Under the action of the electromagnetic field, the magnetostrictive effect produced by the FeGa film causes a change in the propagation velocity of the SAW, and finally the applied current is evaluated with the corresponding differential oscillation frequency offset. In order to further improve the performance of the sensor, the optimized preparation conditions are determined by controlling the preparation processes such as different sputtering power and annealing heat treatment. The experimental results show that when the FeGa film thickness is 500 nm, sputtering power is 100 W, and annealing temperature is 300 ℃, the current sensor has good linearity, repeatability and high sensitivity(up to 24.67 kHz/A).更多还原