A Self-biased Anisotropic Magnetoresistive (AMR) Magnetic Field Sensor on Flexible Kapton

Magnetic Micro and Nano Sensors for Continuous Health Monitoring

“…While the AMR effect is smaller than the GMR and TMR effects, AMR sensors can nevertheless resolve magnetic fields below the mT range and are easier to produce since their layer thicknesses are less critical, and permalloy (Py), as a simple material, can be used for their production [140]. Since AMR sensors can also be printed, they can be prepared on ultrathin polymer foils, which makes them bendable and usable for on-skin applications [141,142]. Oliveros Mata et al showed that an AMR sensor printed using a magnetic paste of Py/Ta flakes and an SBS copolymer on a thin polymer film could detect sub-mT magnetic fields and did not even change its magnetoresistive properties after bending and folding, as depicted in Figure 12 [143].…”

Flexible Sensors—From Materials to Applications

“…Magnetic sensors were generally fabricated using stacked thin films deposited on a flexible substrate. Flexible magnetic sensors based on giant magnetoresistance (GMR) [492][493][494][495], anisotropic magnetoresistance (AMR) [496,497], hall sensors [319,498,499], spin valve [368,500], tunnelling magnetoresistance (TMR) [501,502], and magnetoimpedance (MI) were developed [503]. The most important parameters for flexible magnetic field sensors are sensitivity, magnetic field direction and bendability.…”

“…19 ). An AMR sensor that demonstrated an AMR ratio of 1.2% was fabricated by sequentially depositing permalloy, Au, Pt layers on a PI substrate [497]. Bermúdez et al [496] fabricated an AMR sensor that was able to detect geomagnetic fields (40-60 µT).…”