Spin waves and transport properties in ferromagnetic Co-Al-O and Fe-Al-O granular films: A Brillouin scattering study

Akira Yoshihara; Shigehiro Ohnuma; Hiroyasu Fujimori; Shintaro Nakamura; Tsutomu Nojima

doi:10.1143/JPSJ.77.094704

Spin waves and transport properties in ferromagnetic Co-Al-O and Fe-Al-O granular films: A Brillouin scattering study

Akira Yoshihara, Shigehiro Ohnuma, Hiroyasu Fujimori, Shintaro Nakamura, Tsutomu Nojima

Institute for Materials Research (IMR) (institute affiliation only)

Research output: Contribution to journal › Article › peer-review

8 Citations (Scopus)

Abstract

A systematic Brillouin light scattering (BLS) study on long-wavelength spin waves (SWs) in ferromagnetic TM-Al-O (TM = Co, Fe) nano-granular films with thickness of >1 μm was performed under magnetic fields of up to 4 kOe at room temperature. BLS spectra consist of a pair of bulk SW peaks on both frequency sides and a surface localized SW peak only on the positive frequency side in this study. These SW frequencies as a function of the magnetic field can be fully reproduced by the magnetostatic frequency formula developed for a semi-infinite uniform ferromagnetic medium with an exchange coupling and an in-plane uniaxial magnetic anisotropy. We determined a set of the magnetic constants including the exchange field H_E for each film. Combining the exchange field H_E with the electrical resistivity ρ for each film at room temperature, we found an inverse-square law given by ρ = a(H_E)^-2 for both the Co and Fe granular films with a _Fe = 30:3 μΩ·cm·(kOe)² and a _Co = 22:1 μΩ·cm·(kOe)², respectively.

Original language	English
Article number	094704
Journal	journal of the physical society of japan
Volume	77
Issue number	9
DOIs	https://doi.org/10.1143/JPSJ.77.094704
Publication status	Published - 2008 Sept

Keywords

Brillouin scattering
Exchange coupling
Nanogranular film
Resistivity
Spin wave

ASJC Scopus subject areas

Physics and Astronomy(all)

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10.1143/JPSJ.77.094704

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title = "Spin waves and transport properties in ferromagnetic Co-Al-O and Fe-Al-O granular films: A Brillouin scattering study",

abstract = "A systematic Brillouin light scattering (BLS) study on long-wavelength spin waves (SWs) in ferromagnetic TM-Al-O (TM = Co, Fe) nano-granular films with thickness of >1 μm was performed under magnetic fields of up to 4 kOe at room temperature. BLS spectra consist of a pair of bulk SW peaks on both frequency sides and a surface localized SW peak only on the positive frequency side in this study. These SW frequencies as a function of the magnetic field can be fully reproduced by the magnetostatic frequency formula developed for a semi-infinite uniform ferromagnetic medium with an exchange coupling and an in-plane uniaxial magnetic anisotropy. We determined a set of the magnetic constants including the exchange field HE for each film. Combining the exchange field HE with the electrical resistivity ρ for each film at room temperature, we found an inverse-square law given by ρ = a(HE)-2 for both the Co and Fe granular films with a Fe = 30:3 μΩ·cm·(kOe)2 and a Co = 22:1 μΩ·cm·(kOe)2, respectively.",

keywords = "Brillouin scattering, Exchange coupling, Nanogranular film, Resistivity, Spin wave",

author = "Akira Yoshihara and Shigehiro Ohnuma and Hiroyasu Fujimori and Shintaro Nakamura and Tsutomu Nojima",

year = "2008",

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doi = "10.1143/JPSJ.77.094704",

language = "English",

volume = "77",

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T1 - Spin waves and transport properties in ferromagnetic Co-Al-O and Fe-Al-O granular films

T2 - A Brillouin scattering study

AU - Yoshihara, Akira

AU - Ohnuma, Shigehiro

AU - Fujimori, Hiroyasu

AU - Nakamura, Shintaro

AU - Nojima, Tsutomu

PY - 2008/9

Y1 - 2008/9

N2 - A systematic Brillouin light scattering (BLS) study on long-wavelength spin waves (SWs) in ferromagnetic TM-Al-O (TM = Co, Fe) nano-granular films with thickness of >1 μm was performed under magnetic fields of up to 4 kOe at room temperature. BLS spectra consist of a pair of bulk SW peaks on both frequency sides and a surface localized SW peak only on the positive frequency side in this study. These SW frequencies as a function of the magnetic field can be fully reproduced by the magnetostatic frequency formula developed for a semi-infinite uniform ferromagnetic medium with an exchange coupling and an in-plane uniaxial magnetic anisotropy. We determined a set of the magnetic constants including the exchange field HE for each film. Combining the exchange field HE with the electrical resistivity ρ for each film at room temperature, we found an inverse-square law given by ρ = a(HE)-2 for both the Co and Fe granular films with a Fe = 30:3 μΩ·cm·(kOe)2 and a Co = 22:1 μΩ·cm·(kOe)2, respectively.

AB - A systematic Brillouin light scattering (BLS) study on long-wavelength spin waves (SWs) in ferromagnetic TM-Al-O (TM = Co, Fe) nano-granular films with thickness of >1 μm was performed under magnetic fields of up to 4 kOe at room temperature. BLS spectra consist of a pair of bulk SW peaks on both frequency sides and a surface localized SW peak only on the positive frequency side in this study. These SW frequencies as a function of the magnetic field can be fully reproduced by the magnetostatic frequency formula developed for a semi-infinite uniform ferromagnetic medium with an exchange coupling and an in-plane uniaxial magnetic anisotropy. We determined a set of the magnetic constants including the exchange field HE for each film. Combining the exchange field HE with the electrical resistivity ρ for each film at room temperature, we found an inverse-square law given by ρ = a(HE)-2 for both the Co and Fe granular films with a Fe = 30:3 μΩ·cm·(kOe)2 and a Co = 22:1 μΩ·cm·(kOe)2, respectively.

KW - Brillouin scattering

KW - Exchange coupling

KW - Nanogranular film

KW - Resistivity

KW - Spin wave

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Spin waves and transport properties in ferromagnetic Co-Al-O and Fe-Al-O granular films: A Brillouin scattering study

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