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Title: Distinguishing the laser-induced spin precession excitation mechanism in Fe/MgO(001) through field orientation dependent measurements

Rotational field dependence of laser-induced magnetization precession in a single-crystal Fe/MgO(001) sample was studied by the time resolved magneto-optical Kerr effect. Polar and longitudinal magnetization components were separated by measuring precession dynamics under opposite fields. When the applied field is weaker than the anisotropy field of an Fe film, the precession amplitude is small for the field direction near the easy axis and becomes larger as the field rotates towards the hard axis, showing a four-fold symmetry in agreement with the in-plane magnetic anisotropy; whereas at higher fields, the amplitude displays a drop near the hard axis. Such precession behavior can be well reproduced using an excitation model with rapidly modified but slowly recovered magnetic anisotropy and considering the elliptical precession trajectory. Our results indicate that the dominant mechanism for triggering Fe spin precession is the anisotropy modulation correlating with the lattice thermalization, rather than the transient anisotropy modulation due to the high electron temperature within 1 ps.
Authors:
; ; ;  [1] ;  [2] ;  [1] ;  [3]
  1. Department of Physics, State Key Laboratory of Surface Physics and Advanced Materials Laboratory, Fudan University, Shanghai 200433 (China)
  2. Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Shanghai Ultra-precision Optical Manufacturing Engineering Research Center, and Department of Optical Science and Engineering, Fudan University, Shanghai 200433 (China)
  3. (China)
Publication Date:
OSTI Identifier:
22399200
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 1; 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; ANISOTROPY; CRYSTAL STRUCTURE; ELECTRON TEMPERATURE; EXCITATION; INTERFACES; IRON; KERR EFFECT; LASER RADIATION; MAGNESIUM OXIDES; MAGNETIZATION; MODULATION; MONOCRYSTALS; ORIENTATION; PRECESSION; SPIN; THERMALIZATION; THIN FILMS; TIME RESOLUTION; TRANSIENTS