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Title: Dynamical spin injection at a quasi-one-dimensional ferromagnet-graphene interface

Journal Article · · Applied Physics Letters
DOI:https://doi.org/10.1063/1.4906578· OSTI ID:22415148
; ; ;  [1];  [2];  [2]
  1. Department of Physics, University of Central Florida, Orlando, Florida 32816 (United States)
  2. Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore)

We present a study of dynamical spin injection from a three-dimensional ferromagnet into two-dimensional single-layer graphene. Comparative ferromagnetic resonance (FMR) studies of ferromagnet/graphene strips buried underneath the central line of a coplanar waveguide show that the FMR linewidth broadening is the largest when the graphene layer protrudes laterally away from the ferromagnetic strip, indicating that the spin current is injected into the graphene areas away from the area directly underneath the ferromagnet being excited. Our results confirm that the observed damping is indeed a signature of dynamical spin injection, wherein a pure spin current is pumped into the single-layer graphene from the precessing magnetization of the ferromagnet. The observed spin pumping efficiency is difficult to reconcile with the expected backflow of spins according to the standard spin pumping theory and the characteristics of graphene, and constitutes an enigma for spin pumping in two-dimensional structures.

OSTI ID:
22415148
Journal Information:
Applied Physics Letters, Vol. 106, Issue 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
Country of Publication:
United States
Language:
English