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Title: Enhancing ferromagnetic resonance absorption for very thin insulating magnetic films with spin plasmonics

We consider enhancing the ferromagnetic resonance (FMR) absorption of very thin insulating magnetic films by placing it on top of a dielectric. We find that the signal is enhanced by at least an order of magnitude due to a new nonreciprocal interface resonance that is a mixture of the magnetic surface plasmon mode and a wave guide mode. This resonance occurs over a wide range of thicknesses of the dielectric that is still much less than the wavelength and is made possible by the negative magnetic susceptibility of the magnetic layer. The line width of absorption is reduced by an order of magnitude less than the Gilbert damping parameter. At some frequency, the group velocity of this resonance is negative. Experimentally, very thin yttrium iron garnet (YIG) films are grown on a Gadolinium Gallium Garnet (GGG) substrate which can be considered the dielectric. Our model applies to experiments performed in the YIG/GGG system. Indeed, our picture resolves the disagreement on the magnitude of the spin diffusion lengths obtained with the FMR and the Brillouin scattering techniques. It also provides for a way to make new adaptive thin film miniaturized photonic nonreciprocal devices with low loss.
Authors:
 [1]
  1. Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States)
Publication Date:
OSTI Identifier:
22410174
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 18; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION; BRILLOUIN EFFECT; DIELECTRIC MATERIALS; DIFFUSION LENGTH; FERRITE GARNETS; FERROMAGNETIC RESONANCE; GADOLINIUM COMPOUNDS; GALLIUM OXIDES; INTERFACES; IRON OXIDES; LAYERS; LINE WIDTHS; MAGNETIC SURFACES; MAGNETIC SUSCEPTIBILITY; SPIN; SUBSTRATES; THIN FILMS; YTTRIUM COMPOUNDS