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81. 发明专利

JPH10134335A PERPENDICULAR MAGNETIC RECORDING MEDIUM AND MAGNETIC RECORDING AND REPRODUCING DEVICE FORMED BY USING THE SAME 失效
公开(公告)号：JPH10134335A
公开(公告)日：1998-05-22
申请号：JP23205197
申请日：1997-08-28
申请人： HITACHI LTD
发明人： HIRAYAMA YOSHIYUKI , FUTAMOTO MASAAKI , HONDA YUKIO , YAMANAKA ICHISUKE , ITOU KIYONARI
IPC分类号： G11B5/66 , G11B5/64 , G11B5/65 , G11B5/738 , H01F10/08 , H01F10/16 , H01F10/32
摘要： PROBLEM TO BE SOLVED: To obtain a magnetic recording medium of low noise and high output by using ferromagnetic thin films which are of a specific value or above in coercive force when a magnetic field is impressed on these films in the direction perpendicular to the film plane and are of a specific value or above in the fluctuation field of magnetic viscosity at the magnetic field intensity equal to the coercive force. SOLUTION: The nonmagnetic substrate 11 of the perpendicular magnetic recording medium consists of tempered glass, silicon, titanium alloy, etc., and the ground surface layer 12 thereof consists of titanium or titanium alloy, etc. A magnetic recording layer 13 is formed by using the thin films consisting essentially of Co and Cr and a protective lubricative layer 14 comprises C, Si-C, etc. When the film thickness is reduced, the fluctuation field enlarges and the noise lowers but the coercive force lowers and regenerative output diminishes. The optimum value of S/N exists at 30 to 100nm film thickness. In such a case, the coercive force of the magnetic field impressed on the films in the direction perpendicular to the film plane is >=1500 oersted and the residual magnetization coercive force or the fluctuation field of the magnetic viscosity at the magnetic field intensity equal to the coercive force is >=30 oersted.

82. 发明专利

JPH09128701A PERPENDICULAR MAGNETIC RECORDER 失效
公开(公告)号：JPH09128701A
公开(公告)日：1997-05-16
申请号：JP28564295
申请日：1995-11-02
申请人： HITACHI LTD
发明人： HONDA YUKIO , HIRAYAMA YOSHIYUKI , ITOU KIYONARI , FUTAMOTO MASAAKI
IPC分类号： G11B5/02 , G11B5/127 , G11B5/187
摘要： PROBLEM TO BE SOLVED: To provide the perpendicular magnetic recorder suitable for super high density recording having high line recording density and high track density. SOLUTION: Magnetic recording is performed by using a ring type magnetic head 26 on a perpendicular magnetic recording medium 21 forming a substrate 12, a magnetic layer 13 and a protective layer 14 on a nonmagnetic substrate 11. The magnetic head 26 is constituted to make track width of a leading side magnetic pole and track width of a trailing side magnetic pole equalized with each other, and to align center lines of the track widths of both magnetic poles on the same line and then to make a space Tp between adjacent recording tracks smaller than a gap length of the recording head.

83. 发明专利

JPH08180360A PERPENDICULAR MAGNETIC RECORDING MEDIUM AND MAGNETIC RECORDER 失效
公开(公告)号：JPH08180360A
公开(公告)日：1996-07-12
申请号：JP31795194
申请日：1994-12-21
申请人： HITACHI LTD
发明人： NAKAMURA ATSUSHI , FUTAMOTO MASAAKI , HIRAYAMA YOSHIYUKI , TAKAYAMA TAKANOBU
IPC分类号： G11B5/66 , G11B5/64 , G11B5/73 , G11B5/738
摘要： PURPOSE: To provide a medium excellent in crystal orienting property and having high perpendicular magnetic anisotropy by forming an under film with a Co-Ru alloy. CONSTITUTION: A Co-Ru alloy forms a solid soln. over the entire compsn. range at ordinary temp. and the crystal structure is a hexagonal close-packed structure. An under film 12 of the Co-Ru alloy is formed on a nonmagnetic substrate 11 such as a glass substrate or an NiP coated Al alloy substrate. In the film 12, (0001) faces become parallel to the substrate and c-axes are liable to orient perpendicularly. A perpendicularly magnetized film 13 of a Co-based alloy and a protective film 14 are then formed on the film 12 to obtain the objective perpendicular magnetic recording medium. The proper concn. of Ru is >=40at.% because a compsn. having >=40at.% concn. of Ru gives

84. 发明专利

JPH07141639A MAGNETIC RECORDING MEDIUM AND MAGNETIC RECORDER 失效
公开(公告)号：JPH07141639A
公开(公告)日：1995-06-02
申请号：JP28673693
申请日：1993-11-16
申请人： HITACHI LTD
发明人： NAKAMURA ATSUSHI , HIRAYAMA YOSHIYUKI , FUTAMOTO MASAAKI , INABA NOBUYUKI
IPC分类号： G11B5/66 , G11B5/02 , G11B5/64 , G11B5/65 , G11B5/738
摘要： PURPOSE:To obtain a magnetic recording medium having the magnetic film improved in crystal orientability so as to make the medium fit for high density magnetic recording. CONSTITUTION:A 1st base film 13 having a body-centered cubic structure is formed on a 2nd base film 14 having a CaF2 type crystal structure formed directly on a nonmagnetic substrate 15 or through a certain base film and a magnetic film 12 having a hexagonal close-packed structure is formed on the 1st under film 13. The coercive force and squareness ratio of the resulting magnetic recording medium in the intrasurface direction are enhanced and higher density magnetic recording is enabled.

85. 发明专利

JPH0714144A MAGNETIC RECORDING MEDIUM AND ITS PRODUCTION 失效
公开(公告)号：JPH0714144A
公开(公告)日：1995-01-17
申请号：JP15753393
申请日：1993-06-28
申请人： HITACHI LTD
发明人： FUTAMOTO MASAAKI , NAKAMURA ATSUSHI , INABA NOBUYUKI , HIRAYAMA YOSHIYUKI , MATSUDA YOSHIFUMI , SUZUKI MIKIO , HONDA YUKIO
IPC分类号： C23C14/14 , G11B5/64 , G11B5/66 , G11B5/73 , G11B5/738 , G11B5/85 , H01F10/16 , H01F10/30 , H01F41/20
摘要： PURPOSE:To obtain a magnetic recording medium having line recording density D50, S-N ratio and off-track characteristics as recording and reproducing characteristics improved so as to be made fit for high density magnetic recording. CONSTITUTION:A (110) oriented film 103 of a material having an NaCl type crystal structure and a film 104 of a material having a bcc structure are formed on a nonmagnetic substrate 101 and a magnetic film 105 of a Co-based alloy having an hcp structure is formed on the film 104. The magnetic film 105 may be formed on the (110) oriented film 103. In other way, an underlayer of a material having a bcc structure is formed on a (110) single crystal of a material having an NaCl type crystal structure as a substrate and then a magnetic film of a Co-based alloy having an hcp structure is formed on the underlayer. The magnetic film may directly be formed on the substrate.

86. 发明专利

JPH0714143A MAGNETIC RECORDING MEDIUM AND ITS PRODUCTION 失效
公开(公告)号：JPH0714143A
公开(公告)日：1995-01-17
申请号：JP15753293
申请日：1993-06-28
申请人： HITACHI LTD
发明人： FUTAMOTO MASAAKI , NAKAMURA ATSUSHI , HIRAYAMA YOSHIYUKI , INABA NOBUYUKI , MATSUDA YOSHIFUMI , SUZUKI MIKIO , HONDA YUKIO
IPC分类号： C23C14/14 , G11B5/64 , G11B5/66 , G11B5/73 , G11B5/738 , G11B5/85 , G11B11/10 , G11B11/105 , H01F10/16 , H01F10/30 , H01F41/20
摘要： PURPOSE:To obtain an intrasurface magnetic recording medium improved so as to be made fit for high density magnetic recording. CONSTITUTION:Micro-ruggedness 102, 103 is formed on a base substrate 101, a (100) oriented 1st under film 104 having an NaCl type crystal structure is formed by grapho-epitaxial growth, a 2nd under film 105 having a bcc structure is further disposed and then a magnetic film 106 of a Co-based alloy having an hcp structure is formed on the 2nd under film 105. The magnetic film 106 may directly be formed on the 1st under film 104 without forming the 2nd under film 105. In other way, an under film having a bcc structure is disposed on a (100) single crystal substrate of a material having an NaCl structure and a magnetic film of a Co-based alloy having an hcp structure is formed on the under film. The magnetic film may directly be formed on the single crystal substrate.

87. 发明专利

JPH0696433A ULTRAHIGH DENSITY MAGNETIC RECORDING MEDIUM 失效
公开(公告)号：JPH0696433A
公开(公告)日：1994-04-08
申请号：JP24382992
申请日：1992-09-11
申请人： HITACHI LTD
发明人： TAKEUCHI TERUAKI , HIRAYAMA YOSHIYUKI , FUTAMOTO MASAAKI
IPC分类号： G11B5/66 , G11B5/64 , G11B5/65 , G11B5/73
摘要： PURPOSE:To lower the lower limit of the size of recording bit. CONSTITUTION:When ferromagnetic layers 2 and nonferromagnetic layers 3 are alternately laminated to form a recording film, the thickness of the nonferromagnetic layers 3 is set so that exchange interaction in a direction in which the magnetization directions of two adjacent ferromagnetic layers 2 holding one nonferromagnetic layer 3 between them coincide with each other acts on the two ferromagnetic layers 2 through the nonferromagnetic layer 3. For example, the thickness of the layers 3 is regulated to 1.2-1.8nm. In order to reduce exchange interaction acting through the ferromagnetic layers 2, the layers 2 are made as thin as possible. For example, the thickness of the layers 2 is regulated to density.

88. 发明专利

JPH03205807A METALLIC MULTILAYER FILM AND ITS MANUFACTURE 失效
公开(公告)号：JPH03205807A
公开(公告)日：1991-09-09
申请号：JP67590
申请日：1990-01-08
申请人： HITACHI LTD
发明人： TAKEUCHI TERUAKI , HIRAYAMA YOSHIYUKI , FUTAMOTO MASAAKI , HONDA YUKIO
IPC分类号： G11B5/31 , H01F10/26 , H01F10/32 , H01F41/20
摘要： PURPOSE:To obtain a metallic multilayer film wherein the diffusion of the atoms between layers is so small that one can ignore and the epitaxy to a substrate is favorable by arranging the constitution such that the thickness of the first layer metallic film directly in contact with a substrate is larger than that of each layer of and after the second layer and that it has a region where substrate constituent elements are diffused on the side of the first layer near the boundary between the substrate and the first layer. CONSTITUTION:The thickness of the first layer overlaid directly on a substrate is larger than that of the second layer onward, and besides the vicinity of the boundary with the substrate in the first layer contains substrate constituent elements. For example, using a vacuum deposition method, a multilayer consisting of Fe and Cr is made on a GaAs (100) substrate. In this case, the degree of vacuum during deposition is about 1X10 Torr, and the deposition is performed at a speed of 0.5Angstrom /sec. and the first layer is Cr 500Angstrom in thickness, and this is deposited at a substrate temperature of 250 deg.C, and for the second layer on, Fe 12Angstrom in thickness and Cr 8Angstrom in thickness are deposited alternately in this order by 200 layers each under the substrate of -50 deg.C. In this case, the thickness of the region where Ga atoms are mixed in the first layer becomes about 20Angstrom .

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