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ITE Technical Report, 2009
Physics Procedia, 2011
C-axis orientations of Ru intermediate layer (IML) and CoPtCr-SiO 2 recording layer (RL) are atta... more C-axis orientations of Ru intermediate layer (IML) and CoPtCr-SiO 2 recording layer (RL) are attained by using crystalline FeCoB soft magnetic underlayer (SUL). Better (110) orientation of FeCo improves not only (001) orientation of Ru IML but also that of CoPtCr RL. This leads better perpendicular magnetic anisotropy in the RL suitable for perpendicular magnetic recording media. In order to control the (110) orientation in FeCoB layer, various seed layers are prepared beneath the FeCoB layers. Ru and Si/NiFe seed layers gives FeCoB layer a large in-plane magnetic anisotropy that is effective to suppress spike noise from SUL. The laminated FeCoB SUL causes more improvement of Ru (001) texure and leads to better perpendicular magnetic anisotropy of RL. Ru/CoPtCr-SiO 2 bilayer deposited on laminated FeCoB SUL on Aramid tape substrate has good perpendicular magnetic properties and reduces the noise from SUL.
Spectrochimica Acta Part A: Molecular Spectroscopy, 1988
Abstract The observation of time resolved resonance CARS spectra of fluorene-h 10 and -d 10 in th... more Abstract The observation of time resolved resonance CARS spectra of fluorene-h 10 and -d 10 in their T 1 states in room temperature solution are reported. Observed Raman frequencies are assigned on the basis of a crude normal coordinate calculation of the a 1 fundamentals and a CNDO/S-Cl calculation. The agreement between the calculated and observed values of ν 6 and ν 8 CC stretching frequencies confirms the orbital nature of the T 1 state.
映像情報メディア学会技術報告, Nov 1, 2006
[CoB/Pd]n films were prepared with dc magnetron sputtering and the effect of preparation conditio... more [CoB/Pd]n films were prepared with dc magnetron sputtering and the effect of preparation conditions, the addition of N2 to Ar gas and heating of substrates during the deposition, on its microstructure and magnetic properties were examined.
Wear, 2005
Lubricants are commonly applied onto disks. In this research, studies of the perfluoropolyether (... more Lubricants are commonly applied onto disks. In this research, studies of the perfluoropolyether (PFPE) lubricant effect on the nanowearresistance property of two PFPE-lubricant-coated magnetic perpendicular recording diamond like carbon (DLC) film disks with and without thermal cure were conducted by the lateral oscillation test technique. Using a lateral modulation friction force microscope (LM-FFM), the lateral oscillation wear test was performed by sliding an AFM diamond tip (radius of about 30 nm) over a disk sample while moving the sample in the x direction and simultaneously applying it with a vibration in the y direction. By comparing the surface profile, friction force and dynamic deformation performance of a friction area with those of a no-friction area, the behavior of the lubricant on the surface of the magnetic disk and damage on the magnetic disk were evaluated. The results showed that the wear-resistance property of the disk improved due to the presence of free lubricant on the disk surface. Furthermore, the nanowear properties are compared to the macrodurability properties obtained in oscillation scratch experiments.
Journal of Magnetism and Magnetic Materials, 2012
Perpendicular magnetic recording tape medium with laminated soft magnetic underlayers was success... more Perpendicular magnetic recording tape medium with laminated soft magnetic underlayers was successively formed on a 4.5 mum thin plastic film by the facing targets sputtering method at room temperature. The tape medium showed extremely high SNR values with sharp transitions in playback tests by a drum tester, compared to a linear format commercial tape medium. An areal density of 45.0
Journal of Magnetism and Magnetic Materials, 2008
... Ru-O/Ru/CoPtCr-SiO 2 films prepared at room temperature on Aramid tape substrates exhibited m... more ... Ru-O/Ru/CoPtCr-SiO 2 films prepared at room temperature on Aramid tape substrates exhibited magnetization characteristics suitable for perpendicular magnetic recording media. ... [6] Y. Abe, Y. Kaga, M. Kawamura and K. Sasaki, Jpn. J. Appl. Phys. 40 (12) (2001), p. 6956. ...
Journal of Magnetism and Magnetic Materials, 2008
ABSTRACT Sputtered tape media of a CoPtCr–SiO2 magnetic layer with a Ru underlayer was fabricated... more ABSTRACT Sputtered tape media of a CoPtCr–SiO2 magnetic layer with a Ru underlayer was fabricated on a thin Aramid film by a facing targets sputtering (FTS) system at room temperature with no cooling. Transition electron microscope (TEM) images show columnar epitaxial growth of hcp-CoPtCr(1 0 0) plane on hcp-Ru(1 0 0). Average grain diameter of 10.2 nm with dispersion of 20.2% was obtained from TEM images. Enrichment of Co and Pt inside grains and segregation of Cr and Si to boundary were confirmed by point energy dispersive spectroscopy (EDS) measurements. Playback performance test on sputtered sample indicated that SNR is higher and PW50 value is lower than that of commercial coated tapes. These good playback properties could come from fine and isolated grain structure of magnetic layer of sputtered sample, as observed by TEM.
Journal of Applied Physics, 2012
Si/NiFe seed layers prepared at room temperature is effective to attain better c-axis orientation... more Si/NiFe seed layers prepared at room temperature is effective to attain better c-axis orientation of Ru intermediate layer in the FeCoB/Ru/CoPtCr-SiO2 granular type recording tape media. The crystallinity and c-axis orientation of Ru layer with Si/NiFe seed layers were improved than that without Si/NiFe seed layer deposited on the laminated FeCoB SULs. When the Ru is thicker than 8 nm, Δθ50 of the CoPtCr-SiO2 recording layer shows small value of about 6.5°. Furthermore, even though the Ru thickness was only 3 nm, the Δθ50 retained comparatively small value of 8.0°. Si/NiFe layer is effective as a seed layer for the Ru intermediate layer.
Journal of Applied Physics, 2009
Ru/FeCoB/Ru/CoPtCr–SiO2 films were fabricated as perpendicular magnetic recording media with crys... more Ru/FeCoB/Ru/CoPtCr–SiO2 films were fabricated as perpendicular magnetic recording media with crystalline soft magnetic underlayer (SUL). Ru/FeCoB layers possessed high in-plane anisotropy field Hk of 400 Oe and a bcc-FeCo (110) orientation. Crystalline orientation of the FeCoB in the SUL affected on a crystallite growth of a Ru intermediate layer deposited on it and on crystallite orientation of the CoPtCr–SiO2 film deposited on the Ru intermediate layer. Ru/CoPtCr–SiO2 films without Ru/FeCoB SULs exhibited a random orientation of Ru crystallites and the in-plane magnetic anisotropy. On the other hand, Ru/CoPtCr–SiO2 films deposited on the Ru/FeCoB SULs exhibited (001) preferential orientations of the CoPtCr as well as the Ru intermediate layer and possessed perpendicular magnetic anisotropy. It was confirmed that the improvement of a bcc-FeCo (110) orientation in the SUL was effective to the improvement of a hcp-Ru (001) orientation. At the media for an intermediate layer thickness of 5 nm, the similar m...
Journal of Applied Physics, 2011
A crystalline FeCoB soft magnetic underlayer (SUL) improves c-axis orientations of the Ru interme... more A crystalline FeCoB soft magnetic underlayer (SUL) improves c-axis orientations of the Ru intermediate layer (IML) and the CoPtCr-SiO2 recording layer (RL). (001) orientations of Ru IML and CoPtCr RL are attained by (110) oriented texture of FeCoB SUL. Since good c-axis orientation in CoPtCr-SiO2 RL as well as domain control in the FeCoB SUL is required for high recording
Journal of Applied Physics, 2011
To reduce medium noise inherent in a perpendicular magnetic recording tape, which is deposited by... more To reduce medium noise inherent in a perpendicular magnetic recording tape, which is deposited by facing targets sputtering, we have examined an epitaxial double-layered structure consisting of a soft magnetic underlayer (SUL), bcc-FeCoB/fcc-NiFe/Si/bcc-FeCoB, on a 4.5 mum para-aromatic polyamide (aramid) film. An epitaxial soft magnetic bilayer reduces broadband noise by 5.6 dB at 337 kilo fluxchanges per inch (kfci) compared
IEEE Transactions on Magnetics, 2004
The effects of cross-sectional modulated boron segregation on Co/PdB multilayer perpendicular mag... more The effects of cross-sectional modulated boron segregation on Co/PdB multilayer perpendicular magnetic recording media have been studied. Gradually reduced boron contents from thin PdB seed layer (33 at.%) to the top of the Co(0.2 nm)/PdB (0.8-nm) multilayer (12.5 at.% at the center of the multilayer) were successively achieved and confirmed by the depth-profile of X-ray photoelectron spectroscopy (XPS). Observed magnetic properties and magnetic force microscopy images suggested that this gradient diffusion supports reduction of intergrain exchange coupling and improvement of the magnetic properties. The signal-to-noise ratio over 22 dB was obtained at 450 kFCI in playback tests, in combination with amorphous cobalt boron soft-magnetic underlayer (SUL). It is suggested that these properties are brought by a combination of the dispersed nucleation sites with rich boron content in the initial layer and decreasing boron content during the growth of the multilayer. In addition, this simple medium, which consists of only three elements, Co, Pd, B, for the SUL, the seed layer, and the magnetic layer, has a very unique feature of the dull interfaces, observed by a transmission electron microscope.
IEEE Transactions on Magnetics, 2009
Bcc-FeCo (110) textured Ru/FeCoB films with high in-plane anisotropy field Hk were prepared as cr... more Bcc-FeCo (110) textured Ru/FeCoB films with high in-plane anisotropy field Hk were prepared as crystalline soft magnetic underlayers (SULs). The differences in crystallographic texture of the Ru intermediate layer (IML) and magnetic properties of Ru/CoPtCr-SiO2 films with or without a FeCoB crystalline SUL were investigated. Ru/CoPtCr-SiO2 films without Ru/FeCoB SULs exhibited a random orientation of Ru crystallites and in-plane magnetic anisotropy. On the other hand, Ru/CoPtCr-SiO2 films deposited on the Ru/FeCoB SULs exhibited (001) preferential orientations of the CoPtCr as well as the Ru IMLs and possessed perpendicular magnetic anisotropy. The reduction of the thickness of the Ru IML from 30 nm to 1 nm did not cause the degradation of integrated intensity of the CoPtCr (002) diffraction peak. The application of the Si/NiFe/FeCoB SUL improved the FeCo (110) crystalline orientation, compared to the Ru/FeCoB SUL, and promoted (001) crystalline orientation of the CoPtCr-SiO2 granular recording layer. The correlative relationship between Deltathetas50 of FeCo (110) texture and that of CoPtCr (002) texture was confirmed.
ITE Technical Report, 2009
Physics Procedia, 2011
C-axis orientations of Ru intermediate layer (IML) and CoPtCr-SiO 2 recording layer (RL) are atta... more C-axis orientations of Ru intermediate layer (IML) and CoPtCr-SiO 2 recording layer (RL) are attained by using crystalline FeCoB soft magnetic underlayer (SUL). Better (110) orientation of FeCo improves not only (001) orientation of Ru IML but also that of CoPtCr RL. This leads better perpendicular magnetic anisotropy in the RL suitable for perpendicular magnetic recording media. In order to control the (110) orientation in FeCoB layer, various seed layers are prepared beneath the FeCoB layers. Ru and Si/NiFe seed layers gives FeCoB layer a large in-plane magnetic anisotropy that is effective to suppress spike noise from SUL. The laminated FeCoB SUL causes more improvement of Ru (001) texure and leads to better perpendicular magnetic anisotropy of RL. Ru/CoPtCr-SiO 2 bilayer deposited on laminated FeCoB SUL on Aramid tape substrate has good perpendicular magnetic properties and reduces the noise from SUL.
Spectrochimica Acta Part A: Molecular Spectroscopy, 1988
Abstract The observation of time resolved resonance CARS spectra of fluorene-h 10 and -d 10 in th... more Abstract The observation of time resolved resonance CARS spectra of fluorene-h 10 and -d 10 in their T 1 states in room temperature solution are reported. Observed Raman frequencies are assigned on the basis of a crude normal coordinate calculation of the a 1 fundamentals and a CNDO/S-Cl calculation. The agreement between the calculated and observed values of ν 6 and ν 8 CC stretching frequencies confirms the orbital nature of the T 1 state.
映像情報メディア学会技術報告, Nov 1, 2006
[CoB/Pd]n films were prepared with dc magnetron sputtering and the effect of preparation conditio... more [CoB/Pd]n films were prepared with dc magnetron sputtering and the effect of preparation conditions, the addition of N2 to Ar gas and heating of substrates during the deposition, on its microstructure and magnetic properties were examined.
Wear, 2005
Lubricants are commonly applied onto disks. In this research, studies of the perfluoropolyether (... more Lubricants are commonly applied onto disks. In this research, studies of the perfluoropolyether (PFPE) lubricant effect on the nanowearresistance property of two PFPE-lubricant-coated magnetic perpendicular recording diamond like carbon (DLC) film disks with and without thermal cure were conducted by the lateral oscillation test technique. Using a lateral modulation friction force microscope (LM-FFM), the lateral oscillation wear test was performed by sliding an AFM diamond tip (radius of about 30 nm) over a disk sample while moving the sample in the x direction and simultaneously applying it with a vibration in the y direction. By comparing the surface profile, friction force and dynamic deformation performance of a friction area with those of a no-friction area, the behavior of the lubricant on the surface of the magnetic disk and damage on the magnetic disk were evaluated. The results showed that the wear-resistance property of the disk improved due to the presence of free lubricant on the disk surface. Furthermore, the nanowear properties are compared to the macrodurability properties obtained in oscillation scratch experiments.
Journal of Magnetism and Magnetic Materials, 2012
Perpendicular magnetic recording tape medium with laminated soft magnetic underlayers was success... more Perpendicular magnetic recording tape medium with laminated soft magnetic underlayers was successively formed on a 4.5 mum thin plastic film by the facing targets sputtering method at room temperature. The tape medium showed extremely high SNR values with sharp transitions in playback tests by a drum tester, compared to a linear format commercial tape medium. An areal density of 45.0
Journal of Magnetism and Magnetic Materials, 2008
... Ru-O/Ru/CoPtCr-SiO 2 films prepared at room temperature on Aramid tape substrates exhibited m... more ... Ru-O/Ru/CoPtCr-SiO 2 films prepared at room temperature on Aramid tape substrates exhibited magnetization characteristics suitable for perpendicular magnetic recording media. ... [6] Y. Abe, Y. Kaga, M. Kawamura and K. Sasaki, Jpn. J. Appl. Phys. 40 (12) (2001), p. 6956. ...
Journal of Magnetism and Magnetic Materials, 2008
ABSTRACT Sputtered tape media of a CoPtCr–SiO2 magnetic layer with a Ru underlayer was fabricated... more ABSTRACT Sputtered tape media of a CoPtCr–SiO2 magnetic layer with a Ru underlayer was fabricated on a thin Aramid film by a facing targets sputtering (FTS) system at room temperature with no cooling. Transition electron microscope (TEM) images show columnar epitaxial growth of hcp-CoPtCr(1 0 0) plane on hcp-Ru(1 0 0). Average grain diameter of 10.2 nm with dispersion of 20.2% was obtained from TEM images. Enrichment of Co and Pt inside grains and segregation of Cr and Si to boundary were confirmed by point energy dispersive spectroscopy (EDS) measurements. Playback performance test on sputtered sample indicated that SNR is higher and PW50 value is lower than that of commercial coated tapes. These good playback properties could come from fine and isolated grain structure of magnetic layer of sputtered sample, as observed by TEM.
Journal of Applied Physics, 2012
Si/NiFe seed layers prepared at room temperature is effective to attain better c-axis orientation... more Si/NiFe seed layers prepared at room temperature is effective to attain better c-axis orientation of Ru intermediate layer in the FeCoB/Ru/CoPtCr-SiO2 granular type recording tape media. The crystallinity and c-axis orientation of Ru layer with Si/NiFe seed layers were improved than that without Si/NiFe seed layer deposited on the laminated FeCoB SULs. When the Ru is thicker than 8 nm, Δθ50 of the CoPtCr-SiO2 recording layer shows small value of about 6.5°. Furthermore, even though the Ru thickness was only 3 nm, the Δθ50 retained comparatively small value of 8.0°. Si/NiFe layer is effective as a seed layer for the Ru intermediate layer.
Journal of Applied Physics, 2009
Ru/FeCoB/Ru/CoPtCr–SiO2 films were fabricated as perpendicular magnetic recording media with crys... more Ru/FeCoB/Ru/CoPtCr–SiO2 films were fabricated as perpendicular magnetic recording media with crystalline soft magnetic underlayer (SUL). Ru/FeCoB layers possessed high in-plane anisotropy field Hk of 400 Oe and a bcc-FeCo (110) orientation. Crystalline orientation of the FeCoB in the SUL affected on a crystallite growth of a Ru intermediate layer deposited on it and on crystallite orientation of the CoPtCr–SiO2 film deposited on the Ru intermediate layer. Ru/CoPtCr–SiO2 films without Ru/FeCoB SULs exhibited a random orientation of Ru crystallites and the in-plane magnetic anisotropy. On the other hand, Ru/CoPtCr–SiO2 films deposited on the Ru/FeCoB SULs exhibited (001) preferential orientations of the CoPtCr as well as the Ru intermediate layer and possessed perpendicular magnetic anisotropy. It was confirmed that the improvement of a bcc-FeCo (110) orientation in the SUL was effective to the improvement of a hcp-Ru (001) orientation. At the media for an intermediate layer thickness of 5 nm, the similar m...
Journal of Applied Physics, 2011
A crystalline FeCoB soft magnetic underlayer (SUL) improves c-axis orientations of the Ru interme... more A crystalline FeCoB soft magnetic underlayer (SUL) improves c-axis orientations of the Ru intermediate layer (IML) and the CoPtCr-SiO2 recording layer (RL). (001) orientations of Ru IML and CoPtCr RL are attained by (110) oriented texture of FeCoB SUL. Since good c-axis orientation in CoPtCr-SiO2 RL as well as domain control in the FeCoB SUL is required for high recording
Journal of Applied Physics, 2011
To reduce medium noise inherent in a perpendicular magnetic recording tape, which is deposited by... more To reduce medium noise inherent in a perpendicular magnetic recording tape, which is deposited by facing targets sputtering, we have examined an epitaxial double-layered structure consisting of a soft magnetic underlayer (SUL), bcc-FeCoB/fcc-NiFe/Si/bcc-FeCoB, on a 4.5 mum para-aromatic polyamide (aramid) film. An epitaxial soft magnetic bilayer reduces broadband noise by 5.6 dB at 337 kilo fluxchanges per inch (kfci) compared
IEEE Transactions on Magnetics, 2004
The effects of cross-sectional modulated boron segregation on Co/PdB multilayer perpendicular mag... more The effects of cross-sectional modulated boron segregation on Co/PdB multilayer perpendicular magnetic recording media have been studied. Gradually reduced boron contents from thin PdB seed layer (33 at.%) to the top of the Co(0.2 nm)/PdB (0.8-nm) multilayer (12.5 at.% at the center of the multilayer) were successively achieved and confirmed by the depth-profile of X-ray photoelectron spectroscopy (XPS). Observed magnetic properties and magnetic force microscopy images suggested that this gradient diffusion supports reduction of intergrain exchange coupling and improvement of the magnetic properties. The signal-to-noise ratio over 22 dB was obtained at 450 kFCI in playback tests, in combination with amorphous cobalt boron soft-magnetic underlayer (SUL). It is suggested that these properties are brought by a combination of the dispersed nucleation sites with rich boron content in the initial layer and decreasing boron content during the growth of the multilayer. In addition, this simple medium, which consists of only three elements, Co, Pd, B, for the SUL, the seed layer, and the magnetic layer, has a very unique feature of the dull interfaces, observed by a transmission electron microscope.
IEEE Transactions on Magnetics, 2009
Bcc-FeCo (110) textured Ru/FeCoB films with high in-plane anisotropy field Hk were prepared as cr... more Bcc-FeCo (110) textured Ru/FeCoB films with high in-plane anisotropy field Hk were prepared as crystalline soft magnetic underlayers (SULs). The differences in crystallographic texture of the Ru intermediate layer (IML) and magnetic properties of Ru/CoPtCr-SiO2 films with or without a FeCoB crystalline SUL were investigated. Ru/CoPtCr-SiO2 films without Ru/FeCoB SULs exhibited a random orientation of Ru crystallites and in-plane magnetic anisotropy. On the other hand, Ru/CoPtCr-SiO2 films deposited on the Ru/FeCoB SULs exhibited (001) preferential orientations of the CoPtCr as well as the Ru IMLs and possessed perpendicular magnetic anisotropy. The reduction of the thickness of the Ru IML from 30 nm to 1 nm did not cause the degradation of integrated intensity of the CoPtCr (002) diffraction peak. The application of the Si/NiFe/FeCoB SUL improved the FeCo (110) crystalline orientation, compared to the Ru/FeCoB SUL, and promoted (001) crystalline orientation of the CoPtCr-SiO2 granular recording layer. The correlative relationship between Deltathetas50 of FeCo (110) texture and that of CoPtCr (002) texture was confirmed.