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51. 发明专利

JPH0542725B2 失效
公开(公告)号：JPH0542725B2
公开(公告)日：1993-06-29
申请号：JP13073480
申请日：1980-09-22
申请人： HITACHI LTD
发明人： FUJIWARA HIDEO , KUDO SANEHIRO , TAMURA TEIZO , SUGISHITA NOBUYUKI , SHIROISHI YOSHIHIRO , KIMURA TAKESHI , SHINAGAWA KIMINARI , KUMASAKA TAKAYUKI
IPC分类号： G11B5/127 , G11B5/133 , G11B5/187 , G11B5/193 , G11B5/23 , G11B5/245

52. 发明专利

JPH04278219A MAGNETIC RECORDING MEDIUM AND MAGNETIC MEMORY DEVICE 失效
公开(公告)号：JPH04278219A
公开(公告)日：1992-10-02
申请号：JP4160891
申请日：1991-03-07
申请人： HITACHI LTD
发明人： YAKU SHINAN , SHIROISHI YOSHIHIRO , HISHIYAMA SADAO , ISHIKAWA AKIRA , OONO TSUGUYUKI , YAMAMOTO TOMOO
IPC分类号： G11B5/72 , C09D171/02 , G11B5/64 , G11B5/725
摘要： PURPOSE:To provide a magnetic recording medium which is excellent in sliding resistance and proper to high-density recording and to provide a high-reliability large-capacity magnetic memory device. CONSTITUTION:In a magnetic recording medium having at least one layer of a protective covering layer 14 and 14' on a magnetic layer 13 and 13', the absolute value of an internal stress remaining in the magnetic recording medium 14 and 14' is less than 1GPa. According to the invention, further a magnetic memory device having the magnetic recording medium surface can be provided. The application of the protective covering layer in which the absolute value of the stress remaining inside is less than 1GPa, enhances the adhesion of the magnetic layer and the protection covering layer, which makes it possible to enhance sliding resistance and hence provide a high-reliability and large-capacity magnetic memory device.

53. 发明专利

JPH0422282B2 失效
公开(公告)号：JPH0422282B2
公开(公告)日：1992-04-16
申请号：JP23157389
申请日：1989-09-08
申请人： HITACHI LTD
发明人： FUJIWARA HIDEO , KUDO SANEHIRO , TAMURA TEIZO , SUGISHITA NOBUYUKI , SHIROISHI YOSHIHIRO , KIMURA TAKESHI , SHINAGAWA KIMINARI , KUMASAKA TAKAYUKI
IPC分类号： G11B5/133

54. 发明专利

JPH02226515A MAGNETIC RECORDING MEDIUM 失效
公开(公告)号：JPH02226515A
公开(公告)日：1990-09-10
申请号：JP4539789
申请日：1989-02-28
申请人： HITACHI LTD
发明人： MATSUOKA SHINYA , OURA MASAKI , SHIROKURA TAKAAKI , SHIROISHI YOSHIHIRO
IPC分类号： G11B5/66 , G11B5/64 , G11B5/65 , G11B5/706 , G11B5/73 , G11B5/738
摘要： PURPOSE:To enhance the coercive force of a surface layer and to enhance S/N as well by making the content of Ni in the compsn. of a magnetic layer higher nearer the surface in the film thickness direction of the above-mentioned layer. CONSTITUTION:Cr layers having 250nm film thickness are formed as nonmagnetic underlying layers 12, 12' by a DC magnetron method of 10mTorr Ar gaseous pressure and 3W/cm throwing electric power at 100 deg.C substrate temp. on an Ni-P plated Al alloy substrate 11 which is provided with ruggedness on the surface in the circumferential direction so as to have 10nm center line average height and has 130mm diameter. Lower magnetic layers 13, 13' are formed thereon by the DC magnetron method of the same gaseous pressure, the same substrate temp. and 0.5W/cm throwing electric power and by using a target of compsn. Co72Ni22Zr6 (numerical values are atomic %). Lower magnetic layers 14, 14' are then formed thereon by using the target of Co67Ni27Zr6 and upper magnetic layers 15, 15' by using Co59Ni35Zr6, respectively to 20nm film thickness. C is thereafter formed to 30nm film thickness by the DC magnetron method of the same conditions to form nonmagnetic protective films 16, 16'. The magnetic recording medium is thus obtd.

55. 发明专利

JPH02152008A MAGNETIC RECORDING MEDIUM 失效
公开(公告)号：JPH02152008A
公开(公告)日：1990-06-12
申请号：JP30391488
申请日：1988-12-02
申请人： HITACHI LTD
发明人： SHIROKURA TAKAAKI , OURA MASAKI , SHIROISHI YOSHIHIRO , MATSUOKA SHINYA
IPC分类号： G11B5/66 , G11B5/64 , G11B5/706 , G11B5/716 , G11B5/73
摘要： PURPOSE:To obtain a magnetic recording medium with a magnetic layer having high corrosion resistance and superior magnetic characteristics by forming a lower magnetic layer essentially comprising Co and Ni and an upper magnetic layer comprising Co, Ni and other elements. CONSTITUTION:The lower magnetic layer provided on the side near a nonmagnetic substrate essentially consists of Co and Ni preferably with the compsn. of 10 - 60atomic% of Ni to the total amount of Co and Ni. The upper magnetic layer consists of Co, Ni and at least one element selected from Zr, Ti, Pt, Ru, Ta, Rh, V, Nb, Cr and Pd, and the amount of the third element is preferably 0.1 - 30atomic%. The two-layered structure of the magnetic layer and the material of excellent magnetic characteristics used for the lower magnetic layer improves the magnetic characteristics of the recording medium. Zr contained in the CoNiZr magnetic layer constitutes a dense oxide film near the surface layer, which improves the corrosion resistance.

56. 发明专利

JPH0258723A MAGNETIC RECORDING MEDIUM AND MAGNETIC MEMORY MEDIUM 失效
公开(公告)号：JPH0258723A
公开(公告)日：1990-02-27
申请号：JP20831788
申请日：1988-08-24
申请人： HITACHI LTD
发明人： SHIROISHI YOSHIHIRO , HISHIYAMA SADAO , SUZUKI HIROYUKI , OONO TADAYUKI , YAKU SHINAN , MATSUDA YOSHIFUMI , TAKAGI KAZUMASA , TSUMITA NORIKAZU , OURA MASAKI , SHIGE NORIYUKI
IPC分类号： G11B5/66 , G11B5/64 , G11B5/706 , G11B5/738
摘要： PURPOSE:To decrease the noise level at the time of recording and reproducing and to execute recording and reproducing of information at a high density by incorporating specific materials into magnetic layers formed on a nonmagnetic substrate. CONSTITUTION:The magnetic layer 12, 12' are formed on an alloy which contains Co and Pt and further, contains the material X consisting of the element selected from a 1st group consisting of Ni, Cr, Mo, and W, the material Y' consisting of the element selected form the 2nd group consisting of Ti, Zr, Hf, Ta, Nb, Ru, and Rh and the material Z consisting of the element selected from the 3rd group consisting of Al and Si. The compsn. of the Pt is preferably >=0.1at.% and =1at.% and =1at.% and

57. 发明专利

JPH0249215A MAGNETIC RECORDING MEDIUM AND PRODUCTION THEREOF 失效
公开(公告)号：JPH0249215A
公开(公告)日：1990-02-19
申请号：JP12151189
申请日：1989-05-17
申请人： HITACHI LTD
发明人： FURUSAWA KENJI , ABE KATSUO , KATAOKA HIROYUKI , TAKAGAKI ATSUSUKE , SHIROISHI YOSHIHIRO , TSUMITA NORIKAZU
IPC分类号： G11B5/66 , G11B5/64 , G11B5/65 , G11B5/667 , G11B5/72 , G11B5/73 , G11B5/738 , G11B5/851
摘要： PURPOSE:To obtain the recording medium which decreases modulation by successively laminating at least two layers of sputtered layers of thin chromium films having bow-shaped columnar structures, the sputtered layer of a thin magnetic alloy film and a thin protective film on a nonmagnetic substrate. CONSTITUTION:Ni-P is plated on the Al alloy substrate 11 and thereafter, the surface thereof is polished and textured. The thin Cr films 25 are formed of the Cr layer 12 having the 1st bow-shaped columnar structure projecting in the transporting direction of the substrate 11, the Cr layers 13, 14 having the 2nd, 3rd bow-shaped columnar structures and the thin magnetic film 26 and the protective layer 17 are provided thereon. The substrate 11 is transported in a direction 22 at the time of film formation. The curvature (r) of the bow-shaped columnar layers 12, 13, 14 is specified to about 240nm and the thickness t of the respective layers to about 130nm. The value of r/t in this case is about 1.8. The r/t is about 1 in case of one layer of the thin Cr film consisting of the bow-shaped columnar structure. The columnar structures grow more perpendicularly to the substrate surface as the value of the r/t is larger and, therefore, the magnetic anisotropy in the substrate transporting direction of the magnetic recording medium is decreased and the coercive force Hc uniform in the circumferential direction of the disk is applied. The recording medium which decreases the modulation is thus obtd.

58. 发明专利

JPH027201A MAGNETIC RECORDING AND REPRODUCING DEVICE 失效
公开(公告)号：JPH027201A
公开(公告)日：1990-01-11
申请号：JP15676288
申请日：1988-06-27
申请人： HITACHI LTD
发明人： YAMASHITA TAKEO , KUMASAKA TAKAYUKI , SHIROISHI YOSHIHIRO , OTOMO MOICHI , HISHIYAMA SADAO
IPC分类号： G11B5/02
摘要： PURPOSE:To record and reproduce a signal in recording with high density with a high S/N by providing a means to impress a bias magnetic field less than the coercive force of a recording medium with a large coercive force on a magnetic head in reproduction. CONSTITUTION:The recording and reproduction is performed by combining the recording medium 1 in which at least two or more kinds of materials with different coercive forces are laminated and the magnetic head 2, and the bias magnetic field is impressed on the magnetic head in the reproduction. The recording medium consists of the combination of two or more kinds of magnetic layer with the large coercive force and one with the smaller coercive force. Recording information is recorded on the magnetic layer with the larger coercive force, and the recording information held on the magnetic layer with the large coercive force is transferred on the magnetic layer with the smaller coercive force. At the time of reproducing the recording information, it is performed by impressing the bias magnetic field on the magnetic head. In such a way, larger reproducing output can be obtained, and also, a frequency characteristic can be improved remarkably.

59. 发明专利

JPH01263910A PERPENDICULAR MAGNETIC RECORDING MEDIUM AND MAGNETIC DISK DEVICE 失效
公开(公告)号：JPH01263910A
公开(公告)日：1989-10-20
申请号：JP8905888
申请日：1988-04-13
申请人： HITACHI LTD
发明人： MATSUDA YOSHIFUMI , SHIROISHI YOSHIHIRO , HISHIYAMA SADAO , SUZUKI HIROYUKI , OONO TADAYUKI , SAITO SHINICHIRO , TAKAGI KAZUMASA
IPC分类号： G11B5/66 , G11B5/64 , G11B5/65 , G11B5/667 , G11B5/706 , G11B5/73 , G11B5/738
摘要： PURPOSE:To improve magnetic characteristics and adhesiveness so as to obtain a high recording density and to improve reliability by using intermediate layers of a Ti-alloy contg. specific elements in addition to Ti as nonmagnetic intermediate layers. CONSTITUTION:The thin films added with at least one kind of the element selected from the group consisting of V, Nb, Ta, Cr, Mo, W, Mn, Ni, Pd, Pt, Cu, Ag, Au, C, Si, Ge, Ru, Os, Rh, and Ir are used for the intermediate layers 13, 13' of the Ti-base alloy of the perpendicular magnetic recording medium provided with the intermediate layers 13, 13' of the Ti-base alloy between hexagonal magnetic alloy layers 14, 14' and a nonmagnetic substrate 11. The c-axis orientational property and magnetic characteristics of the hexagonal magnetic alloy layers 14, 14' are thereby greatly improved and the magnetic disk and device having the good recording and reproducing characteristics and reliability are thereby obtd.

60. 发明专利

JPS6472313A MAGNETIC RECORDING MEDIUM 失效
公开(公告)号：JPS6472313A
公开(公告)日：1989-03-17
申请号：JP22830287
申请日：1987-09-14
申请人： HITACHI LTD
发明人： OONO TADAYUKI , MITSUYA MUNEHISA , KUDO TAKANORI , SHIROISHI YOSHIHIRO , HISHIYAMA SADAO , SUZUKI HIROYUKI , MATSUDA YOSHIFUMI
IPC分类号： G11B5/66 , C10M105/54 , C10N40/18 , G11B5/72 , G11B5/725 , G11B5/73
摘要： PURPOSE:To obtain a lubricating film which has a small film thickness, low spacing loss and small adhesion and obviates an increase in the friction of the surface by forming a protective film on the surface of a magnetic film and forming a monomolecular film of a specific org. compd. on the surface of this protective film as the lubricating film. CONSTITUTION:The protective film 5 formed on the magnetic film 4 consisting of a thin ferromagnetic metallic film formed on a substrate 1 and the org. lubricating film 6 of the monomolecular film which is formed on the protective film and consists of the chemical formula Rf-R-A are provided to a magnetic recording medium having the substrate 1 and the above-mentioned magnetic film 4. In the formula, Rf denotes a perfluoroalkyl group; R denotes an alkyl group or fluoroalkyl group; A denotes a polar group. The arrangement of the molecules is thereby uniformized and the surface energy is decreased to the level smaller than the surface energy of a multilayer film. The coefft. of friction is lowered as well and the film functions as the thinner and better lubricating film.

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