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beta-NMR Investigation of the Depth-Dependent Magnetic Properties of an Antiferromagnetic Surface

Titlebeta-NMR Investigation of the Depth-Dependent Magnetic Properties of an Antiferromagnetic Surface
Publication TypeJournal Article
Year of Publication2016
AuthorsCortie, DL, Buck, T, Dehn, MH, Karner, VL, Kiefl, RF, Levy, CDP, McFadden, RML, Morris, GD, McKenzie, I, Pearson, MR, Wang, XL, MacFarlane, WA
JournalPHYSICAL REVIEW LETTERS
Volume116
Pagination106103
Date PublishedMAR 10
ISSN0031-9007
Abstract

By measuring the prototypical antiferromagnet alpha-Fe2O3, we show that it is possible to determine the static spin orientation and dynamic spin correlations within nanometers from an antiferromagnetic surface using the nuclear spin polarization of implanted Li-8(+) ions detected with beta-NMR. Remarkably, the first-order Morin spin reorientation in single crystal alpha-Fe2O3 occurs at the same temperature at all depths between 1 and 100 nm from the (110) surface; however, the implanted nuclear spin experiences an increased 1/T-1 relaxation rate at shallow depths revealing soft-surface magnons. The surface-localized dynamics decay towards the bulk with a characteristic length of epsilon = 11 +/- 1 nm, closely matching the finite-size thresholds of hematite nanostructures.

DOI10.1103/PhysRevLett.116.106103