NIST scientists image ring magnets using SEMPA - News Briefs - Brief Article

Journal of Research of the National Institute of Standards and Technology, Jan, 2002

Researchers at NIST, in collaboration with the University of Cambridge, Thin Film Magnetism Group, have used the NIST Scanning Electron Microscopy with Polarization Analysis (SEMPA) facility to directly image the magnetic domain structure of mesoscopic ring magnets. These micrometer sized rings and discs, patterned out of cobalt thin-films, are the basis for new types of nonvolatile, magnetic random access memories, and the SEMPA measurements provided the first images of various magnetic structures occurring in the magnets.

Some of the magnetic structures that were observed agree with predictions based on earlier, non-spatially-resolved, magnetization measurements of these films. However, additional, unexpected domain wall structures were also found to exist. Knowledge about the nanoscale magnetic structure of the various magnetic states and how the states switch from one to another provides critical information needed to determine whether these patterned magnetic structures will make useful, reproducible magnetic memories.

CONTACT: John Unguris, (301) 975-3712; john. unguris@nist.gov.