Nanoscale magnetic media diagnostics by rippling spin waves

Memory devices based on magnetism are one of the core technologies of the computing industry, and engineers are working to develop new forms of magnetic memory that are faster, smaller and more energy efficient than today’s flash and SDRAM memory. They now have a new tool developed by a team from the National Institute of Standards and Technology (NIST), the University of Maryland Nanocenter and the Royal Institute of Technology in Sweden -- a method to detect defects in magnetic structures as small as a tenth of a micrometer even if the region in question is buried inside a multilayer electronic device. Trapped beneath the magnetic tip of a microscale cantilever, spin waves can be used to non-destructively measure the properties of magnetic materials and search for nanoscale defects, especially in multilayer magnetic systems like a typical hard drive, where defects could be buried beneath the surface. The technique demonstrated at the NIST Center for Nanoscale Technology (CNST) builds on work by researchers at the Ohio State University. The idea is to trap and image oscillating perturbations of a magnetic field -- 'spin waves -- in a thin film. Trapped spin waves provide scientists with a powerful new tool to nondestructively measure the properties of magnetic materials and search for nanoscale defects that could or have caused memory failures, especially in multilayer magnetic systems like a typical hard drive, where defects could be buried beneath the surface.