Nonmonotonic inelastic tunneling spectra due to surface spin excitations in ferromagnetic junctions

Mesoscopic and Nanoscale Systems
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Abstract

The paper addresses inelastic spin-flip tunneling accompanied by surface spin excitations (magnons) in ferromagnetic junctions. The inelastic tunneling current is proportional to the magnon density of states which is energy-independent for the surface waves and, for this reason, cannot account for the bias-voltage dependence of the observed inelastic tunneling spectra. This paper shows that the bias-voltage dependence of the tunneling spectra can arise from the tunneling matrix elements of the electron-magnon interaction. These matrix elements are derived from the Coulomb exchange interaction using the itinerant-electron model of magnon-assisted tunneling. The results for the inelastic tunneling spectra, based on the nonequilibrium Green’s function calculations, are presented for both parallel and antiparallel magnetizations in the ferromagnetic leads.

Keywords

Tunneling Spectrum Inelastic Contribution Tunneling Matrix Element Inelastic Tunneling Ferromagnetic Lead 

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Copyright information

© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  1. 1.Institute for Theoretical Physics, Regensburg UniversityRegensburgGermany
  2. 2.Institute for Theoretical Physics and Astrophysics, Würzburg UniversityWürzburgGermany

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