Silva Marilia, Franco Fernando, Leitao Diana C, Cardoso Susana, Freitas Paulo P
Instituto de Engenharia de Sistemas e Computadores - Microsistemas e Nanotecnologias (INESC-MN), 1000-029, Lisbon, Portugal.
Instituto Superior Tecnico (IST), Universidade de Lisboa, 1040-001, Lisbon, Portugal.
Sci Rep. 2021 Jan 8;11(1):215. doi: 10.1038/s41598-020-79856-0.
A new device architecture using giant magnetoresistive sensors demonstrates the capability to detect very low magnetic fields on the pT range. A combination of vertically packed spin-valve sensors with two-dimensional in-plane arrays, connected in series and in parallel, delivers a final detection level of 360 pT/[Formula: see text] at 10 Hz at room temperature. The device design is supported by an analytical model developed for a vertically packed spin-valve system, which takes into account all magnetic couplings present. Optimization concerning the spacer thickness and sensor physical dimensions depending on the number of pilled up spin-valves is necessary. To push the limits of detection, arrays of a large number of sensing elements (up to 440,000) are patterned with a geometry that improves sensitivity and in a configuration that reduces the resistance, leading to a lower noise level. The final device performance with pT detectivity is demonstrated in an un-shielded environment suitable for detection of bio-signals.
一种采用巨磁阻传感器的新型器件架构展示了检测皮特斯拉（pT）范围内极低磁场的能力。垂直堆叠的自旋阀传感器与二维平面内阵列相结合，串联和并联连接，在室温下10赫兹时的最终检测水平为360 pT/[公式：见原文]。该器件设计得到了为垂直堆叠自旋阀系统开发的分析模型的支持，该模型考虑了所有存在的磁耦合。根据堆叠的自旋阀数量对间隔层厚度和传感器物理尺寸进行优化是必要的。为了突破检测极限，大量传感元件（多达440,000个）的阵列采用了提高灵敏度的几何结构和降低电阻的配置进行图案化，从而降低了噪声水平。在适合生物信号检测的非屏蔽环境中展示了具有皮特斯拉探测能力的最终器件性能。
