Increased magnetic damping in ultrathin films of Co2FeAl with perpendicular anisotropy

Y. K. Takahashi*, Y. Miura, R. Choi, T. Ohkubo, Z. C. Wen, K. Ishioka, R. Mandal, R. Medapalli, H. Sukegawa, S. Mitani, E. E. Fullerton, K. Hono

*Corresponding author for this work

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18 Citations (Scopus)

Abstract

We estimated the magnetic damping constant α of Co2FeAl (CFA) Heusler alloy films of different thicknesses with an MgO capping layer by means of time-resolved magneto-optical Kerr effect and ferromagnetic resonance measurements. CFA films with thicknesses of 1.2 nm and below exhibited perpendicular magnetic anisotropy arising from the presence of the interface with MgO. While α increased gradually with decreasing CFA film thickness down to 1.2 nm, it was increased substantially when the thickness was reduced further to 1.0 nm. Based on the microstructure analyses and first-principles calculations, we attributed the origin of the large α in the ultrathin CFA film primarily to the Al deficiency in the CFA layer, which caused an increase in the density of states and thereby in the scatterings of their spins.

Original languageEnglish
Article number252409
JournalApplied Physics Letters
Volume110
Issue number25
DOIs
Publication statusPublished - 2017 Jun 19
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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