Versatile Green Transfer of Magnetoelectronics with Loss-Free Performance and High Adhesion for Interactive Electronics

A stringent quality requirement for a nm-thick multi-stack heterostructures and delicate antiferromagnetic interlayer couplings inherent to giant magnetoresistive (GMR) sensors limits their seamless integration on objects with non-planar surfaces and/or biological structures. Here, a green transfer method of high performance and mechanically robust GMR sensors to a wide range of biological, organic, and inorganic substrates is demonstrated. Importantly, the transfer technique relies on water and biocompatible polyvinyl alcohol (PVA) polymer and requires no complex treatments that involve harsh chemicals and conditions, allowing for transferring sensors causing no harm to the environment. A high surface tension of water employed in the transfer process ensures a smooth spreading of the sensor film reinforced by the hydrophilic PVA layer, mitigating stress concentrations in the GMR film and preserving its structural integrity. Transferred sensors maintain their performance, low noise, and reveal excellent mechanical stability even after 3000 bending cycles. This green transfer technique of GMR sensors fosters various applications, e.g., to function as a human-machine interface in wearable and interactive electronics.