Kim Kun Woo, Reddy Venu, Torati Sri Ramulu, Hu Xing Hao, Sandhu Adarsh, Kim Cheol Gi
Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 711-873, Republic of Korea.
Lab Chip. 2015 Feb 7;15(3):696-703. doi: 10.1039/c4lc01076k.
An on-chip magnetometer was fabricated by integrating a planar Hall magnetoresistive (PHR) sensor with microfluidic channels. The measured in-plane field sensitivities of an integrated PHR sensor with NiFe/Cu/IrMn trilayer structure were extremely high at 8.5 μV Oe(-1). The PHR signals were monitored during the oscillation of 35 pL droplets of magnetic nanoparticles, and reversed profiles for the positive and negative z-fields were measured, where magnitudes increased with the applied z-field strength. The measured PHR signals for 35 pL droplets of magnetic nanoparticles versus applied z-fields showed excellent agreement with magnetization curves measured by a vibrating sample magnetometer (VSM) of 3 μL volume, where a PHR voltage of 1 μV change is equivalent to 0.309 emu cc(-1) of the volume magnetization with a magnetic moment resolution of ~10(-10) emu.
通过将平面霍尔磁阻（PHR）传感器与微流体通道集成，制造了一种片上磁力计。具有NiFe/Cu/IrMn三层结构的集成PHR传感器的面内场灵敏度极高，为8.5 μV Oe⁻¹。在35 pL磁性纳米颗粒液滴振荡期间监测PHR信号，并测量了正z场和负z场的反向曲线，其幅度随施加的z场强度增加。对于35 pL磁性纳米颗粒液滴，测量的PHR信号与3 μL体积的振动样品磁力计（VSM）测量的磁化曲线显示出极好的一致性，其中1 μV变化的PHR电压相当于体积磁化强度为0.309 emu cc⁻¹，磁矩分辨率约为10⁻¹⁰ emu。
