Highly compliant planar Hall effect sensor with sub 50 nT sensitivity

GRANELL, PABLO; WANG, GUOLIANG ; CAÑON BERMUDEZ, GILBERT S. ; KOSUB, TOBIAS ; GOLMAR, FEDERICO ; STEREN, LAURA ; FASSBENDER, JURGEN ; MAKAROV, DENYS; GOLMAR, FEDERICO ; STEREN, LAURA ; FASSBENDER, JURGEN ; MAKAROV, DENYS

Conferencia; MMM / INTERMAG 2019; 2019

Next generation of flexible appliances such as soft robots aim to become fully autonomousand will require ultra-thin and flexible navigation modules, body tracking and relative position monitoringsystems, which typically include magnetic field sensors as key building blocks. Although there is a greatprogress in the field of shapeable magnetoelectronics [1], there is no technology available which can enablesensitivities to magnetic fields lower than 1 μT (below the geomagnetic field) in a mechanically compliant formfactor. To address this challenging task we introduced a new fundamental effect towards magnetic field sensing--the planar Hall effect (PHE) [2-5]-- in the field of shapeable magnetoelectronics. We demonstrate that evenwhen prepared on mechanically imperceptible 6-μm-thick polymeric foils, magnetic field sensors based on theplanar Hall effect have a remarkable sensitivity of 0.86 V/T and are capable of detecting magnetic fields in therange of sub 50 nT. Furthermore, these sensors can be bent to a radius of 1 mm without any degradation oftheir electrical resistance and shows excellent cyclic bending performance with only 0.3% resistance variationafter more than 150 bending cycles. The application potential of the device is showcased in two examples ofan angle and proximity sensors. For the latter, we demonstrate that the compliant PHE sensor is able to detectsmall magnetic stray fields of magnetically functionalized objects as needed for conventional metrology as wellas point of care diagnostics. High sensitivity of the prepared sensing devices combined with a remarkablesimplicity of fabrication, is a step forward in the realization of cost efficient flexible magnetoelectronic devices,with possible application in soft robotics, interactive devices for virtual- and augmented reality [6,7] and point ofcare platforms for the detection of magnetic objects [8].