Pt\Co\W as a candidate for low power nanomagnetic logic

Pt\Co\W multilayers are evaluated as a novel material composition for the use in perpendicular nanomagnetic logic (pNML) applications. Starting from single and bilayer stacks, the material system is explored for maximum Co thicknesses while preserving perpendicular magnetic anisotropy (PMA) as well as single-domain behavior for micrometer-sized structures. Results for single trilayers show significantly reduced saturation magnetizations when compared to Pt\Co\Pt. Anisotropy measurements reveal a comparable volume component together with substantially reduced surface contributions. The subsequent analysis of [Co-1.22\Pt-1.45\W-X](2) bilayer stacks indicates the emergence of weak interlayer coupling superposed by anisotropy differences, for Tungsten thicknesses t(W) >= 0.5 nm, not exceeding the low mT range. The impact of local anisotropy engineering on micromagnetic test structures by means of Ga+ ion beam irradiation for different stack compositions is investigated, targeting low nucleation fields and shaping hysteresis behaviors for single step switching. First operational dipole-coupled inverter structures based on a Pt\Co\Heavy-Metal system are demonstrated achieving clocking fields down to 50 mT.