Modelling the sensitivity of infrared emissivity of magnetic thin films to giant magnetoresistance

S. M. Stirk, S. M. Thompson, J. A. D. Matthew

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The correlation between emissivity and giant magnetoresistance (GMR) in magnetic thin films is investigated at infrared (IR) wavelengths using a thin-film model of emissivity. The sensitivity of emissivity to GMR is shown to depend upon film thickness, and agrees excellently with bulk-material results for films thicker than the material skin depth. However, for films thinner than the skin depth the sensitivity to GMR is shown to weaken. In addition, at mid-to-far IR wavelengths the spectral dependence of the correlation is investigated using a modified Drude-type expression for the refractive index combined with the thin-film model. This is applied to a multilayered GMR material, and the sensitivity of emissivity to GMR is shown to have a similar spectral dependence to that of the magnetorefractive effect. An analytical interpretation in terms of skin depth is also developed at long wavelengths, and shown to agree excellently with thin-film simulations. (c) 2008 Elsevier B. V. All rights reserved.

Original languageEnglish
Pages (from-to)354-360
Number of pages7
JournalJournal of Magnetism and Magnetic Materials
Issue number5
Publication statusPublished - Mar 2009


  • Emissivity
  • Infrared
  • Giant magnetoresistance
  • Remote sensing
  • Magnetorefractive effect

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