STRETCHABILITY AND SELF-HEALING OF WRINKLED GMR MULTILAYERS ON ELASTOMERIC MEMBRANES

Stretchable magneto-resistive sensing elements have been introduced lately as a novel component providing magnetic functionality to stretchable consumer electronics involving smart skin or medical diagnostic applications. While spin valves already revealed high stretchability and reliability, GMR multilayers still lack mechanical compliance and production yield. Here, we report on two crucial improvements in fabrication of GMR multilayers to address these limiting issues. On the one hand, we increase the stretchability of wrinkled magnetic nanomembranes on freestanding elastomer membranes by photolithographically structuring them into a meander pattern. The meander can be regarded as a 2D spring, which can accommodate tensile strains in addition to the apparent wrinkling. On the other hand, we highlight a self-healing effect of GMR multilayers, which occurs due to a thermally induced pre-strain in the elastic support. This causes the soft membrane to contract after the GMR elements are prepared on top and closes cracks often induced during fabrication. Relying on this feature we are able to restore the full GMR performance, even if the magneto-sensitive element initially appeared to be without electrical contact before contraction of the free-standing soft membrane.