TY - JOUR
T1 - Magnetic microstructures of nano-granular CoPt-Al-O thin films studied by lorentz microscopy and electron holography
AU - Park, H. S.
AU - Shindo, D.
AU - Mitani, S.
AU - Takanashi, K.
N1 - Funding Information:
This work was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science, Sports and Culture of Japan, and by the Special Coordination Funds for Promoting Science and Technology of “Nanohetero Metallic Materials” from the Science and Technology Agency.
PY - 2005/10
Y1 - 2005/10
N2 - Microstructures and magnetic domain structures of nano-granular CoPt-Al-O thin films are investigated by Lorentz microscopy and electron holography. It is found that the CoPt-based nanocrystalline phases are basically surrounded by the Al2 O3-based amorphous phases and the area of the Al2O3 -based amorphous phases increases with the increase in oxygen content. Typical mazy domains and domain walls like fishbone are observed in the Co45.8Pt18.6Al17.3O 18.3 and in localized area of the Co38.7Pt 15.6Al16.3O29.4, respectively, while no magnetic domain walls are observed in the Co34.4Pt 13.5Al15.63O36.5. With the increase in magnetic field, domain walls like fishbone start to disappear and the magnetic flux density increases in the Co38.7Pt15.6Al 16.3O29.4, indicating the mixed-phase state of ferromagnetic and superparamagnetic phases. In the Co34.4Pt 13.5Al15.6O36.5 of superparamagnetic state, the fluctuated lines of magnetic flux are considered to reflect the randomly magnetized distribution of CoPt-based single domain particles.
AB - Microstructures and magnetic domain structures of nano-granular CoPt-Al-O thin films are investigated by Lorentz microscopy and electron holography. It is found that the CoPt-based nanocrystalline phases are basically surrounded by the Al2 O3-based amorphous phases and the area of the Al2O3 -based amorphous phases increases with the increase in oxygen content. Typical mazy domains and domain walls like fishbone are observed in the Co45.8Pt18.6Al17.3O 18.3 and in localized area of the Co38.7Pt 15.6Al16.3O29.4, respectively, while no magnetic domain walls are observed in the Co34.4Pt 13.5Al15.63O36.5. With the increase in magnetic field, domain walls like fishbone start to disappear and the magnetic flux density increases in the Co38.7Pt15.6Al 16.3O29.4, indicating the mixed-phase state of ferromagnetic and superparamagnetic phases. In the Co34.4Pt 13.5Al15.6O36.5 of superparamagnetic state, the fluctuated lines of magnetic flux are considered to reflect the randomly magnetized distribution of CoPt-based single domain particles.
KW - Electron holography
KW - Lines of magnetic flux
KW - Magnetic domain structure
KW - Nano-granular thin film
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U2 - 10.1109/TMAG.2005.854674
DO - 10.1109/TMAG.2005.854674
M3 - Article
AN - SCOPUS:27744547249
VL - 41
SP - 3724
EP - 3726
JO - IEEE Transactions on Magnetics
JF - IEEE Transactions on Magnetics
SN - 0018-9464
IS - 10
ER -