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

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.
Authors:
; ; ;  [1] ;  [2] ;  [3] ;  [2] ;  [3] ;  [3] ;  [4]
  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)
  3. (Singapore)
  4. (NGS), National University of Singapore, Singapore 117456 (Singapore)
Publication Date:
OSTI Identifier:
22415148
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; FERROMAGNETIC MATERIALS; FERROMAGNETIC RESONANCE; GRAPHENE; LAYERS; MAGNETIZATION; SPIN; THREE-DIMENSIONAL LATTICES; TWO-DIMENSIONAL SYSTEMS