巨磁电阻传感器对铁磁流体的动态检测 .pdfVIP

学兔兔 第32卷 第5期 仪 器 仪 表 学 报 V01．32 No．5 2011年5月 Chinese Journal of Scientific Instrument Mav．2011 巨磁电阻传感器对铁磁流体的动态检测术 石海平，冯 洁，陈 翔，李福泉 (上海交通大学微纳科学技术研究院 上海 200240) 摘 要：研究一种集成微流道的巨磁电阻(GMR)传感器对铁磁流体的动态检测。利用su一8胶和PDMS键合在巨磁电阻传感 器上集成微流道。铁磁流体为直径10 llm的Fe O 悬浮溶液。巨磁电阻传感器通过直接测量铁磁流体流过有效检测区域时磁 珠的感应场，实现对铁磁流体的动态检测。为使检测的灵敏度最大，综合考虑了外加磁场对传感器灵敏度和磁珠感应场的影 响。实验结果表明巨磁电阻传感器能够检测到铁磁流体的流动，且传感器信号与微流道中铁磁流体的磁珠浓度成正比。 关键词：巨磁电阻；磁传感器；铁磁流体；微流体 中图分类号：TP212 文献标识码：A 国家标准学科分类代码：510．30 Dynamic detection of ferrofluid with giant magnet0resistance sensor Shi Haiping，Feng Jie，Chen Xiang，Li Fuquan (National Key Laboratory of Micro／Nano Fabrication Technology，Shanghai Jiaotong University， Shanghai 200240，China) Abstract：A giant magnetoresistance(GMR) sensor with integrated microfludic channel was studied for the dynamic detection of ferrofluid．The microfludic channel is integrated by SU-8 glue and PDMS bonding．The ferrofluid is a 10 nm Fe3 O4 suspension．The dynamic detection is carried out by directly measuring the~inge fields generated from superparamagnetic beads when the ferrofluid passes the active sensing area of a GMR sensor．To maximizing the de- tection sensitivity，the effect ofthe applied magnetic fields on both the sensor sensitivity and bead fringe fields is taken into account．Experiment resuhs show that GMR sensors can detect the ferrofluid flow，and the sensor signals are proportional to the bead concentration of the ferrofluid in the microfludic channe1． Key words：giant magnetoresistance；magnetic sensor；ferrofluid；mierofluid 生物传感器按巨磁电阻的形成机理又可分为多层膜结构 1 引