Integrated Giant Magnetoresistance Technology for Approachable Weak Biomagnetic Signal Detections

Abstract

With the extensive applications of biomagnetic signals derived from active biological tissue in both clinical diagnoses and human-computer-interaction, there is an increasing need for approachable weak biomagnetic sensing technology. The inherent merits of giant magnetoresistance (GMR) and its high integration with multiple technologies makes it possible to detect weak biomagnetic signals with micron-sized, non-cooled and low-cost sensors, considering that the magnetic field intensity attenuates rapidly with distance. This paper focuses on the state-of-art in integrated GMR technology for approachable biomagnetic sensing from the perspective of discipline fusion between them. The progress in integrated GMR to overcome the challenges in weak biomagnetic signal detection towards high resolution portable applications is addressed. The various strategies for 1/f noise reduction and sensitivity enhancement in integrated GMR technology for sub-pT biomagnetic signal recording are discussed. In this paper, we review the developments of integrated GMR technology for in vivo/vitro biomagnetic source imaging and demonstrate how integrated GMR can be utilized for biomagnetic field detection. Since the field sensitivity of integrated GMR technology is being pushed to fT/Hz0.5 with the focused efforts, it is believed that the potential of integrated GMR technology will make it preferred choice in weak biomagnetic signal detection in the future.

Ultrasensitive Magnetic Field Sensors for Biomedical Applications

“…Although being a well-established technology, magnetoresistance magnetometers continue to advance. The equivalent noise level has reduced down to a few pT/ √ Hz [80][81][82] in the low-frequency regime [23,83]. Nowadays, AMR [84], GMR [85], and TMR [86] sensors are the main technologies based on the magnetoresistance effect.…”

Miniaturized Magnetic Sensors for Implantable Magnetomyography

“…[ 17,89 ] We showed that such simulation results and parameters can be extracted and imported to the Cadence Spectre simulator for integration with a CMOS‐based readout circuit. [ 39,90–94 ] We believe that this structure can offer a platform to develop ultra‐sensitive, smart and compact sensors for MMG sensing. To reliably compile the TMR model in the Cadence environment, we adopted a FEM environment such as COMSOL Multiphysics.…”

Advances in Magnetoresistive Biosensors

“…The other kind of MFCs is based on soft-ferromagnetic materials [69]. By concentrating the magnetic flux into the senor region, these MFCs are capable of increasing the sensitivity by hundreds of times while working at room temperature [70]. It was shown that by integrating MTJs with a CoCrPt permanent magnet and a CoZrNb MFC, the lowest detectable field of 49 pT/Hz 0.5 was achieved [71] (Figure 4).…”