Elastic GMR (giant magnetoresistance) sensor with strain-invariant properties

Elastic GMR (giant magnetoresistance) sensor with strain-invariant properties

Source: Melzer M. et al. Nature Communications 6 6080 (2015)

The current establishment of stretchable electronics to form a seamless link between soft or even living materials and the digital world is at the forefront of multidisciplinary research efforts, bridging physics, engineering and materials science. The emerging commercial products of wearable electronics are only the beginning of this trend. Soon, multifunctional electronics will readily conform to ubiquitous objects of arbitrary shapes, including the human skin, being re-shapeable on demand after its fabrication.

A variety of compliant electronic elements with various functions have been realized during the last years, which are able to reversibly accommodate tensile strains far beyond the intrinsic ductility of the active electronic materials they are made of, without sacrificing their performance. Magnetic functionalities can provide a touchless sense of displacement, orientation or proximity to this novel formulation of electronics.

This work reviews the recent development of stretchable magnetic field sensorics, from the demonstration of the world’s first elastically stretchable magnetic sensing element to the realization of a technology platform for scalable and robust, ready-to-use elastic magnetosensorics. With the research summarized in this review, key attributes, i.e. sensitivity, stretchability, miniaturization and durability, were improved by about two orders of magnitude compared to the original sensor design. Currently, magnetosensitive elements exhibiting the same sensing performance as on conventional rigid supports, but with fully strain invariant properties up to 270% stretching are available. A variety of novel technologies, like electronic skins, smart textiles, soft robotics and actuators, active medical implants and soft consumer electronics will benefit from these new magnetic functionalities.

A review on stretchable magnetic field sensorics
M. Melzer, D. Makarov and O. G. Schmidt
Journal of Physics D: Applied Physics, Vol. 53, No. 8 (open access)
BAM Division Sensors, Measurement and Testing Methods