Synthetic antiferromagnets with perpendicular magnetic anisotropy (PMA-SAFs) have gained growing attention for both conventional and next generation spin-based technologies. While the progress of PMA-SAF spintronic devices on rigid substrates has been remarkable, only few examples of flexible thin film heterostructures are reported in the literature, all containing platinum group metals (PGMs). Systems based on Co/Ni may offer additional advantages with respect to devices containing PGMs, i.e., low damping and high spin polarization. Moreover, limiting the use of PGMs may relieve the demand for critical raw materials and reduce the environmental impact of related technologies, thus contributing to the transition toward a more sustainable future.
In this work, an international team of researchers from different institutions (CNR-ISM nM2-Lab, Italy; Universität Augsburg, Germany; Politecnico di Milano, Italy; Università Politecnica delle Marche, Italy; CNR-IMEM, Italy; CNR-ISMN, Italy) reported for the first time on the realization of Co/Ni-based PMA-SAFs on polymer tapes and exploited it to obtain flexible PMA giant magneto-resistive spin valves (GMR-SVs). High-quality flexible SAFs with a fully compensated antiferromagnetic region and SVs with a sizable GMR ratio (up to 4.4%), in line with the values reported in the literature for similar systems on rigid substrates, were obtained.
These results, along with the high robustness of the samples’ properties against bending (up to 180°), indicate that complex and bendable Co/Ni-based heterostructures with reduced content of PGMs can be obtained on flexible tapes, allowing for the development of novel flexible and sustainable spintronic devices for applications in many fields including wearable electronics, soft robotics, and biomedicine.
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