Brillouin light scattering from collective spin waves in Fe-Al-O granular films

Akira Yoshihara, Wei Dong Li, Osamu Kitakami, Yutaka Shimada

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


Spin waves (SWs) propagating along the inplane easy and hard directions of highly resistive and soft magnetic Fe67Al13O20 granular films of ∼ 1 μm in thickness have been studied at room temperature by Brillouin light scattering in magnetic fields of up to 4.0kOe. The granular films possess an isotropic inplane resistivity of ρ ∼ 150 μΩ cm and exhibit an inplane magnetic anisotropy of HK ∼ 150 Oe. We also examined SWs of a polycrystalline Fe film of ∼ 1 μm in thickness. SW spectra observed from the granular films consist of a bulk SW peak on both frequency sides and a surface SW peak only on the positive frequency side in this study, and are very similar to the SW spectra of the Fe film. Also, the SW peak widths of the granular films are found to be comparable to the SW peak widths of the Fe film. Magnetostatic analyses for a uniform medium with an anisotropic exchange coupling and an inplane uniaxial magnetic anisotropy successfully reproduce the SW frequencies as a function of the magnetic field. We found that the SW stiffness constants in the Fe-Al-O granular films are highly anisotropic; the easy-axis constant can be more than 10 times larger than the hard-axis constant.

Original languageEnglish
Pages (from-to)257-263
Number of pages7
JournalJournal of Magnetism and Magnetic Materials
Issue number1-2
Publication statusPublished - 2004 Jan


  • Brillouin scattering
  • Exchange coupling
  • Fe-Al-O
  • Granular film
  • Spin wave

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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