Granular nanostructures and magnetic characteristics of FePt-TiO 2/FePt-C stacked granular films

Takuya Ono; Tomohiro Moriya; Masatoshi Hatayama; Nobuaki Kikuchi; Satoshi Okamoto; Osamu Kitakami; Takehito Shimatsu

doi:10.1063/1.4861684

Granular nanostructures and magnetic characteristics of FePt-TiO ₂/FePt-C stacked granular films

Takuya Ono, Tomohiro Moriya, Masatoshi Hatayama, Nobuaki Kikuchi, Satoshi Okamoto, Osamu Kitakami, Takehito Shimatsu

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

3 Citations (Scopus)

Abstract

To realize a granular film composed of L1₀-FePt grains with high uniaxial magnetic anisotropy energy, K_u, and segregants for heat-assisted magnetic recording, the FePt-TiO₂/FePt-C stacked film was investigated. The FePt-TiO₂/FePt-C stacked film has well-isolated granular structure with average grain size of 6.7 nm because the FePt-TiO ₂ film follows the FePt-C template film in microstructural growth. However, the K_u value is quite low for total thickness of 9 nm: 5 × 10⁶ erg/cm³. Exploration of the thickness dependence of L1₀-FePt(001) peaks in XRD spectra and cross-sectional TEM images suggest that degradation of the L1₀ ordering appears near the middle of the FePt-TiO₂ layer. The EDX-STEM mapping reveals that Ti atoms exist within the FePt grains in addition to the grain boundary. This indicates the possibility that TiO₂ tends to be incorporated into the FePt grains and that it prevents L1₀-ordering of the FePt grains along the normal-to-plane direction.

Original language	English
Article number	17B709
Journal	Journal of Applied Physics
Volume	115
Issue number	17
DOIs	https://doi.org/10.1063/1.4861684
Publication status	Published - 2014 May 7

ASJC Scopus subject areas

Physics and Astronomy(all)

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title = "Granular nanostructures and magnetic characteristics of FePt-TiO 2/FePt-C stacked granular films",

abstract = "To realize a granular film composed of L10-FePt grains with high uniaxial magnetic anisotropy energy, Ku, and segregants for heat-assisted magnetic recording, the FePt-TiO2/FePt-C stacked film was investigated. The FePt-TiO2/FePt-C stacked film has well-isolated granular structure with average grain size of 6.7 nm because the FePt-TiO 2 film follows the FePt-C template film in microstructural growth. However, the Ku value is quite low for total thickness of 9 nm: 5 × 106 erg/cm3. Exploration of the thickness dependence of L10-FePt(001) peaks in XRD spectra and cross-sectional TEM images suggest that degradation of the L10 ordering appears near the middle of the FePt-TiO2 layer. The EDX-STEM mapping reveals that Ti atoms exist within the FePt grains in addition to the grain boundary. This indicates the possibility that TiO2 tends to be incorporated into the FePt grains and that it prevents L10-ordering of the FePt grains along the normal-to-plane direction.",

author = "Takuya Ono and Tomohiro Moriya and Masatoshi Hatayama and Nobuaki Kikuchi and Satoshi Okamoto and Osamu Kitakami and Takehito Shimatsu",

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T1 - Granular nanostructures and magnetic characteristics of FePt-TiO 2/FePt-C stacked granular films

AU - Ono, Takuya

AU - Moriya, Tomohiro

AU - Hatayama, Masatoshi

AU - Kikuchi, Nobuaki

AU - Okamoto, Satoshi

AU - Kitakami, Osamu

AU - Shimatsu, Takehito

PY - 2014/5/7

Y1 - 2014/5/7

N2 - To realize a granular film composed of L10-FePt grains with high uniaxial magnetic anisotropy energy, Ku, and segregants for heat-assisted magnetic recording, the FePt-TiO2/FePt-C stacked film was investigated. The FePt-TiO2/FePt-C stacked film has well-isolated granular structure with average grain size of 6.7 nm because the FePt-TiO 2 film follows the FePt-C template film in microstructural growth. However, the Ku value is quite low for total thickness of 9 nm: 5 × 106 erg/cm3. Exploration of the thickness dependence of L10-FePt(001) peaks in XRD spectra and cross-sectional TEM images suggest that degradation of the L10 ordering appears near the middle of the FePt-TiO2 layer. The EDX-STEM mapping reveals that Ti atoms exist within the FePt grains in addition to the grain boundary. This indicates the possibility that TiO2 tends to be incorporated into the FePt grains and that it prevents L10-ordering of the FePt grains along the normal-to-plane direction.

AB - To realize a granular film composed of L10-FePt grains with high uniaxial magnetic anisotropy energy, Ku, and segregants for heat-assisted magnetic recording, the FePt-TiO2/FePt-C stacked film was investigated. The FePt-TiO2/FePt-C stacked film has well-isolated granular structure with average grain size of 6.7 nm because the FePt-TiO 2 film follows the FePt-C template film in microstructural growth. However, the Ku value is quite low for total thickness of 9 nm: 5 × 106 erg/cm3. Exploration of the thickness dependence of L10-FePt(001) peaks in XRD spectra and cross-sectional TEM images suggest that degradation of the L10 ordering appears near the middle of the FePt-TiO2 layer. The EDX-STEM mapping reveals that Ti atoms exist within the FePt grains in addition to the grain boundary. This indicates the possibility that TiO2 tends to be incorporated into the FePt grains and that it prevents L10-ordering of the FePt grains along the normal-to-plane direction.

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