TY - JOUR
T1 - High-Frequency Soft Magnetic Properties of Co-SiO2 Nanogranular Films With Large Out-of-Plane Magnetic Anisotropy
AU - Kijima-Aoki, Hanae
AU - Takeda, Shigeru
AU - Ohnuma, Shigehiro
AU - Masumoto, Hiroshi
N1 - Funding Information:
This work was supported by the Japan Society for the Promotion of Science KAKENHI under Grant-in-aid 17H03385. The authors thank Dr. T. Miyazaki of Tohoku University for his support in performing TEM observations. The authors also thank Dr. M. Naoe of DENJIKEN for his considerable help and technical assistance.
PY - 2018/6/27
Y1 - 2018/6/27
N2 - For their use as flexible frameworks in high-frequency electromagnetic devices, soft magnetic thin films must have a high relative permeability μ up to frequencies of the order of 10 GHz and must overcome directional limitations. In this study, we demonstrate full in-plane, high-frequency, soft magnetic performance of Cox-(SiO2)1-x nanogranular films with large out-of-plane anisotropy. For a film with Co concentration x = 0.52, we obtained a high value μ = 4 up to the resonance frequency of 13 GHz for every direction in the film plane. The fine magnetic-maze-domain structure that we observed using magnetic force microscopy was unaffected by the application of an external magnetic field. Both the large out-of-plane anisotropy fields of a few thousand oersteds and the negligibly small remanent magnetization contribute to produce a resonance frequency greater than 10 GHz and to enable magnetically isotropic conditions in the film plane, with high reversibility in external magnetic fields. This film with the large out-of-plane anisotropy promises to be a useful material for applications in fully directional and flexible designs of electromagnetic devices.
AB - For their use as flexible frameworks in high-frequency electromagnetic devices, soft magnetic thin films must have a high relative permeability μ up to frequencies of the order of 10 GHz and must overcome directional limitations. In this study, we demonstrate full in-plane, high-frequency, soft magnetic performance of Cox-(SiO2)1-x nanogranular films with large out-of-plane anisotropy. For a film with Co concentration x = 0.52, we obtained a high value μ = 4 up to the resonance frequency of 13 GHz for every direction in the film plane. The fine magnetic-maze-domain structure that we observed using magnetic force microscopy was unaffected by the application of an external magnetic field. Both the large out-of-plane anisotropy fields of a few thousand oersteds and the negligibly small remanent magnetization contribute to produce a resonance frequency greater than 10 GHz and to enable magnetically isotropic conditions in the film plane, with high reversibility in external magnetic fields. This film with the large out-of-plane anisotropy promises to be a useful material for applications in fully directional and flexible designs of electromagnetic devices.
KW - Microwave magnetics
KW - eddy current
KW - high-frequency permeability
KW - magnetic maze domains
KW - nanogranular films
KW - out-of-plane magnetic anisotropy
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U2 - 10.1109/LMAG.2018.2849713
DO - 10.1109/LMAG.2018.2849713
M3 - Article
AN - SCOPUS:85049125126
VL - 9
JO - IEEE Magnetics Letters
JF - IEEE Magnetics Letters
SN - 1949-307X
M1 - 3704205
ER -