Spin Transport in Thin Copper Channels Fabricated via Thermal Scanning Probe Lithography
A. J. Wright, D. Bromley, O. J. Barker, S. B. Tekin, I. Z. Mitrovic, C. Leighton, L. O'BrienABSTRACT
Non‐local spin valves (NLSVs) are a useful platform for probing spin transport phenomena but are almost exclusively fabricated using electron‐beam lithography (EBL). Here, we demonstrate, for the first time, the fabrication of all‐metallic NLSVs using thermal scanning probe lithography (t‐SPL). We optimize the t‐SPL fabrication process for a bilayer resist stack, and we successfully fabricate NLSVs with ∼100 nm nanowire widths, strong spin signals and clean ferromagnetic switching. We use this platform to investigate spin‐transport in thin (25 nm) Cu channels, observing weak temperature dependence of the spin‐diffusion length and near temperature‐independence of the interface spin polarization. Analysis of the spin‐relaxation efficiency using Elliot–Yafet theory indicates enhanced defect and phonon spin‐relaxation, consistent with enhanced surface effects in the thin‐channel regime. These results establish t‐SPL as a viable nanofabrication technique and a useful tool for the development of nanoscale spintronic devices.