Evaluation of damping constants for Co/Pt multilayers and CoPt alloy films

Yusaku Kusanagi, Satoshi Okamoto Nobuaki Kikiichi, Osamu Kitakami, Takeshi Kato, Satoshi Ivvata

Research output: Contribution to journalArticlepeer-review

Abstract

In this study, the damping constants of Co/Pt multilayers and hexagonal-closed-packed (hcp) CoPt alloy films are investigated by using a vector network analizer ferromagnetic resonance spectroscopy (VNA-FMR) and time resolved magneto-optical Ken- effect (TR-MOKE). For Co/Pt multilayer films, very clear linear relationship between FMR frequency and absorption peak width is found. From this relationship, the damping constants of Co/Pt multilayers are evaluated to be about 0.02 - 0.07 with very small extrinsic contributions. On the other hand, for CoPt alloy films, the absorption peak width becomes wider and exhibits very little FMR frequency dependence. The damping constants of CoPt alloy films evaluated by TR-MOKE. however, are as small as about 0.03 - 0.06. being almost the same with that Co/Pt multilayers. These discrepancies found in CoPt alloy films can be explained by assuming the large distribution of magnetic anisotropy. Thus the damping constant of CoPt alloy films are some what larger than that of Co/Pt multilayers when these results are compared at same Pt composition.

Original languageEnglish
Pages (from-to)317-323
Number of pages7
JournalIEEJ Transactions on Fundamentals and Materials
Volume136
Issue number5
DOIs
Publication statusPublished - 2016

Keywords

  • Co/Pt multilayer film Co
  • Damping constant
  • Ferromagnetic resonance
  • Perpendicular magnetic film
  • Pt alloy film

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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