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Displaying 1-14 of 14 articles from this issue
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Article type: Cover
Pages Cover1-
Published: November 20, 1997
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (15K) -
Article type: Index
Pages Toc1-
Published: November 20, 1997
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (69K) -
S.Y. Hong, T.D. Lee, K.H. ShinArticle type: Article
Pages 1-5
Published: November 20, 1997
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSWe have investigated the possibility of using CoTi intermetallic compound as a novel underlayer material for Co alloy longitudinal recording media. A CoTi underlayer showed strong (200) single peak when deposited on substrates heated higher than 250 ℃ and thicker than 30 nm. When CoCrPt layer was subsequently deposited on CoTi (200) planes, Co (1120) single peak was developed. The coercivity increased from 2000 Oe to 2500 Oe with increasing thickness of CoTi underlayer from 30 nm to 200 nm. CoTi shows a smaller grain size than Cr and CoCrPt/CoTi showed 500 to 600 Oe higher coercivity than CoCrPt/Cr deposited on a same condition. Crystallographic texture development of CoTi with varying substrate temperature and varying film thickness was studied by X-ray and grain morphology was examined by TEM.View full abstractDownload PDF (479K) -
Toshiaki KEITOKU, Jun ARIAKE, Naoki HONDA, Kazuhiro OUCHIArticle type: Article
Pages 7-12
Published: November 20, 1997
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThe effects of Yttrium as the third additive metals on magnetic properties of Co-Cr alloy thin film media with a high saturation magnetization (Ms) have been studied. It was found that 1.4-2.8at% Y addition to Co-Cr caused 100-150℃ higher substrate temperature for the maximum value in perpendicular coercivities (Hc_⊥) and anisotropy fields (Hk_⊥) than that of Co-Cr, and the maximum values of both Hc_⊥ and Hk_⊥ for Co-Cr-Y were larger than that for Co-Cr. Addition of Y seemed successful in reducing the degree of magnetic coupling between particles. The region for Hc_⊥ greater than 2000 Oe in the mapping on film thickness and substrate temperature was broadened by Y addition in terms of magnetic film thickness. The ratio of Hc_⊥/Hk_⊥ for the Y addition was the highest among those for the other elements additions.View full abstractDownload PDF (618K) -
Setsuo YAMAMOTO, Toshihiko HAYASHI, Hiroki KURISU, Mitsuru MATSUURAArticle type: Article
Pages 13-17
Published: November 20, 1997
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSA novel sputtering apparatus using a magnetron sputtering cathode and inductively-coupled-plasma (ICP) generation was built to use in Co-Cr film deposition. In this sputtering apparatus, flexible control of plasma characteristics and ion bombardment is possible. In this study, the plasma bombardment was changed by applying substrate bias voltage in the range of -50 to +100V. When the plasma assist is small, the deposited Co-Cr film showed low perpendicular coercivity and small perpendicular magnetic anisotropy. From this result and the same kind of experimental results obtained using sputtering using electron-cyclotron-resonance (ECR) microwave plasma, we may conclude that the Co-Cr films with high perpendicular coercivity and large perpendicular magnetic anisotropy are obtained when a moderate ion bombardment was supplied during film deposition.View full abstractDownload PDF (469K) -
Hyeong-Jun Kim, Byung-II Lee, Seung-Ki JooArticle type: Article
Pages 19-24
Published: November 20, 1997
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSMetallic ferromagnetic thin films such as a 500Å of Co, Fe and Ni films were prepared on Si (111) and 4° tilt-cut Si (111) substrates with a 50Å of Cu buffer layer and the effects of tilt-cut Si substrates on the crystallinity and magnetic anisotropy of the films were investigated. From the measurement of M-H curves and a revised X-ray diffraction (XRD) study, it was found that 4° tilt-cut Si (111) substrates are effective to obtain a film of uniaxial magnetic anisotropy with a preferred orientation. When the correlation of crystal structure and magnetic anisotropy was analyzed in each Co, Fe, Ni film on Si (111) and 4° tilt-cut Si (111) substrates, it was observed that a transition of crystallinity from close packed structure to less packed structure is accompanied by a transition of magnetic anisotropy according as the substrate is varied from Si (111) to 4° tilt-cut Si(111). It has been believed that the tilt-cut Si substrates are useful for many technological applications in viewpoint of easy development of various magnetic anisotropies by a control of film growth and structures.View full abstractDownload PDF (425K) -
Shigeki NAKAGAWA, Seiryu TAKAYAMA, Kyung Hwan KIM, Masahiko NAOEArticle type: Article
Pages 25-30
Published: November 20, 1997
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSAlthough Ti and Co_<67>Cr_<33> underlayers improve the crystallinity and c-axis orientation in Co-Cr and Co-Cr-Ta recording layers deposited on them, H_<c⊥> of them were degraded even though they were deposited at high substrate temperature T_s. Better crystallinity seem, to suppress the segregation. The increase of M_s of Co_<67>Cr_<33> layers deposited at higher T_s seemed to be caused by segregation process. The rocking curve profiles split into two peaks when the films were deposited at T_s in the range from 100 to 250℃. The segregated phase grains grew in the films with inclining their c-axis from the normal direction.View full abstractDownload PDF (634K) -
Naoki HONDA, Takanori KIYA, Kazuhiro OUCHIArticle type: Article
Pages 31-36
Published: November 20, 1997
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSA noise source model based on fine reversed domain structure was proposed from perpendicular recording media, and semi-quantitative expressions for noise and signal to noise ratio was obtained containing macroscopic parameters. It was indicated that higher SQ_⊥ along with smaller reversed domain size is effective to reduced the medium noise and the intrinsic medium noise spectrum has a white noise property. The efficiency of the analysis was confirmed by experiments for integrated noise and noise spectra. It was also suggested that Co-Cr based perpendicular recording media have much room for the improvement in terms of noise property.View full abstractDownload PDF (769K) -
Hiroshi YOSHIKAWA, Toshifumi OHKUBO, Kenji FUKUZAWA, Manabu YAMAMOTOArticle type: Article
Pages 37-42
Published: November 20, 1997
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThe transition characteristics of the near-field intensity above a periodical grating sample was investigated using a microfabricated photocantilever operated in non-contact constant-height mode. We examined the intensity transition of the spatial frequency terms that comprise the near-field image, within the scan height range of 60 to 120 nm above the sample surface common in current hard disk drives. An analytical model is proposed to explain for the the experimental results, qualitatively. We were able to obtain a resolution of 250 nm when scanned 60 nm above the sample surface. This suggests that the photocantilever is capable of obtaining higher resolution required for high density recording well within the non-contact scan height range used in hard disk drive technology.View full abstractDownload PDF (648K) -
Young-Seok KIM, Sung-Chul SHINArticle type: Article
Pages 43-47
Published: November 20, 1997
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSPerpendicular magnetic anisotropy (PMA) at room temperature in Ni/Pt multilayer thin films were obtanined for the samples of constant-3-Å Pt and 9〜16 Å Ni sublayer thicknesses, prepared by sequential dc magnetron sputter deposition. Accurate stress and magnetostriction measurements revealed that stress-induced magnetoelastic anisotropy was a major origin for the observed PMA in this system.View full abstractDownload PDF (349K) -
Jaekyong CHOArticle type: Article
Pages 49-54
Published: November 20, 1997
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThis paper reviews the techniques that have been developed and proposes a new scheme to reduce media noise of garnet films. Garnet films have greater magneto-optic figure of merit by a factor of ten at around 500 nm compared to the amorphous rare-earth transition metal alloy films currently being used as magneto-optic recording media. However, all garnet media measured to date exhibited poorer carrier to noise ration than the a-RE-TM media showed due to the significant media noise that is attributed to their polycrystalline microstructure. Among various efforts have been made the seed layer and the rapid thermal annealing techniques were effective to reduce the average grain size and inhomogeneity of the garnet films. In this paper, a new scheme that combines the seed layer and RTA techniques is proposed and discussed for further improvements of the morphology of the garnet films.View full abstractDownload PDF (508K) -
Euibok LEE, Jaekyong CHOArticle type: Article
Pages 55-60
Published: November 20, 1997
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSPolycrystalline La-substituted Bi : YIG films with chemical compositions of La_xBi_<0.5>Y_<2.5>Fe_4AlO_<12> (x=0,0.2,0.6,0.8,1.0,1.2) have been prepared by pyrolysis. The optical absorption coefficient, the Faraday rotation, and the apparent Kerr rotation spectra of the films were investigated in the wavelengths ranging of 400-700 nm. The optical absorption coefficient at the wavelengths ranging 450-550nm were decreased as La content increased. Both the Faraday rotation coefficient and the apparent Kerr rotation angle were enhanced by La-substitution in the wavelengths ranging 420-460 nm. As a result the magneto-optic figure of merit for the Faraday configuration as well as for the Kerr configuration was increased in the wavelengths ranging 420-460 nm. The origin of the increased figure of merit is discusse.View full abstractDownload PDF (404K) -
Chung Ping LIU, Der Ray HUANG, Yung Yuan CHANG, Cheng Kuang LEE, E Van ...Article type: Article
Pages 61-65
Published: November 20, 1997
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThe crystallization properties of GsSbTe recording film prepared by rfmagnetron magnetron sputtering process were analyzed using various characterization techniques. The crystalline-to-crystalline transition occurred in the film could be confirmed. The results show that the first stage appeared in crystallization process was the meta-stable fcc phase. Consequently, the crystalline state used in practical dynamic testing was the meta-stable fcc phase, not hexagonal phase.View full abstractDownload PDF (311K) -
Article type: Appendix
Pages App1-
Published: November 20, 1997
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (76K)
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