Time-resolved magnetization dynamics and damping constant of sputtered Co/Ni multilayers

T. Kato, Y. Matsumoto, S. Okamoto, N. Kikuchi, O. Kitakami, N. Nishizawa, S. Tsunashima, S. Iwata

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37 Citations (Scopus)


Co/Ni multilayers with a stack of Ta (2 nm)/[Co(tCo)/Ni(t Ni)]N/Ta (30 nm) were prepared by dc magnetron sputtering, and their magnetization dynamics were measured by time-resolved magneto-optical Kerr effect (TRMOKE). The total thickness of the multilayer and perpendicular anisotropy were varied by changing the bilayer period d = tCo+ t Ni and number of repeats N while tNi/tCo was kept at a constant of 2.5. The TRMOKE measurements show clear damped oscillation of the magnetization of Co/Ni multilayers after the pump pulse illumination, and the damping constant α of the Co/Ni multilayers was estimated from the TRMOKE waveform. The estimated α was found to be independent both on total thickness and anisotropy field of the multilayer and was estimated to be ∼0.035 for all the multilayers. This means that the use of Ta capping and buffer layers is effective to evaluate intrinsic damping constant of the Co/Ni multilayer, and that independent control of α and perpendicular anisotropy are possible for the magnetic multilayers.

Original languageEnglish
Article number6027700
Pages (from-to)3036-3039
Number of pages4
JournalIEEE Transactions on Magnetics
Issue number10
Publication statusPublished - 2011 Oct


  • Co/Ni multilayer
  • Gilbert damping
  • magnetization dynamics
  • time-resolved magneto-optical Kerr effect (TRMOKE)

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

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