Magnetic recording medium

• US 5,989,672 A
• Filed: 03/25/1997
• Issued: 11/23/1999
• Est. Priority Date: 11/19/1992
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Hayashi, Shigenori
• Primary Examiner(s): KILIMAN, LESZEK B
• Application Number:
  US08/823,541
• Time in Patent Office: 973 Days
• Field of Search: 428/694 T, 428/694 TP, 428/694 TC, 428/694 TR, 428/141, 428/336, 428/408, 428/704, 428/698, 428/65.3, 428/65.5, 428/900
• US Class Current: 428/833.2
• CPC Class Codes: G11B 5/72 Protective coatings, e.g. anti-static or antifriction
• CPC Class Codes: G11B 5/8408 protecting the magnetic layer
• CPC Class Codes: Y10S 428/90 Magnetic feature
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• CPC Class Codes: Y10T 428/265 1 mil or less
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer

Abstract

A magnetic recording medium having a diamond-like carbon (DLC) film added therein a Group IV element of the periodic table such as silicon, particularly in the vicinity of the boundary between the magnetic material and the formed DLC film. Since a DLC having low friction coefficient can be formed, the centerline average roughness can be reduced to 30 nm or even less. Accordingly, a magnetic recording medium improved in magnetic properties and in lubricity can be obtained.

Claims

1. A magnetic recording medium comprising:

a substrate;

a coating comprising carbon including SP³ carbon bond provided over said substrate; and

a magnetic layer provided between said substrate and said coating,

wherein said coating contains an element selected from the group consisting of silicon, germanium, tin and lead.

2. A magnetic recording medium according to claim 1 wherein said coating contains 1 to 15% by atomic of silicon as said element.

3. A magnetic recording medium according to claim 1 wherein a surface of said coating has a center line average height of 30 nm or less.

4. A magnetic recording medium according to claim 1 wherein said magnetic layer comprises a Co--Ni alloy.

5. A magnetic recording medium according to claim 1 wherein said magnetic layer comprises a metal.

6. A magnetic recording medium according to claim 1 wherein said coating comprises carbon including SP³ carbon bond and SP² carbon bond.

7. A magnetic recording medium according to claim 1 wherein concentration of said element is decreased toward a surface of said coating.

8. A magnetic recording medium according to claim 1 wherein said magnetic layer comprises CoPtCr.

9. A magnetic recording medium according to claim 1 wherein said magnetic layer comprises ferrite.

10. A magnetic recording medium according to claim 1 wherein said substrate comprises an organic material or a metal.

11. A magnetic recording medium comprising:

a substrate;

a coating comprising carbon including SP³ carbon bond provided over said substrate; and

a magnetic layer provided between said substrate and said coating,

wherein said coating contains an element selected from the group consisting of silicon, germanium, tin and lead, and

wherein said coating has a thickness of 10 to 200Å

.

12. A magnetic recording medium according to claim 11 wherein said coating contains 1 to 15% by atomic of silicon as said element.

13. A magnetic recording medium according to claim 11 wherein a surface of said coating has a center line average height of 30 nm or less.

14. A magnetic recording medium according to claim 11 wherein said magnetic layer comprises a Co--Ni alloy.

15. A magnetic recording medium according to claim 11 wherein said magnetic layer comprises a metal.

16. A magnetic recording medium according to claim 11 wherein said coating comprises carbon including SP³ carbon bond and SP² carbon bond.

17. A magnetic recording medium according to claim 11 wherein concentration of said element is decreased toward a surface of said coating.

18. A magnetic recording medium according to claim 11 wherein said magnetic layer comprises CoPtCr.

19. A magnetic recording medium according to claim 11 wherein said magnetic layer comprises ferrite.

20. A magnetic recording medium according to claim 11 wherein said substrate comprises an organic material or a metal.

21. A magnetic recording medium comprising;

a substrate;

a coating comprising carbon including SP³ carbon bond provided over said substrate; and

a magnetic layer provided between said substrate and said coating,

wherein said coating contains hydrogen and an element selected from the group consisting of silicon, germanium, tin and lead, and

wherein said hydrogen functions as a terminator of a dangling bond in said coating.

22. A magnetic recording medium according to claim 21 wherein said coating contains 1 to 15% by atomic of silicon as said element.

23. A magnetic recording medium according to claim 21 wherein a surface of said coating has a center line average height of 30 nm or less.

24. A magnetic recording medium according to claim 21 wherein said magnetic layer comprises a Co--Ni alloy.

25. A magnetic recording medium according to claim 21 wherein said magnetic layer comprises a metal.

26. A magnetic recording medium according to claim 21 wherein said coating comprises carbon including SP³ carbon bond and SP² carbon bond.

27. A magnetic recording medium according to claim 21 wherein concentration of said element is decreased toward a surface of said coating.

28. A magnetic recording medium according to claim 21 wherein said magnetic layer comprises CoPtCr.

29. A magnetic recording medium according to claim 21 wherein said magnetic layer comprises ferrite.

30. A magnetic recording medium according to claim 21 wherein said substrate comprises an organic material or a metal.

31. A magnetic recording medium according to claim 21 wherein said coating contains hydrogen from 10 to 60% by atomic.

32. A magnetic recording medium comprising:

a substrate;

a coating comprising carbon including SP³ carbon bond provided over said substrate; and

a magnetic layer provided between said substrate and said coating,

wherein said coating contains an element selected from the group consisting of silicon, germanium, tin and lead, and

wherein said coating further contains an element selected from the group consisting of boron, aluminum, gallium, nitrogen, phosphorus and arsenic.

33. A magnetic recording medium according to claim 32 wherein said coating contains 1 to 15% by atomic of silicon.

34. A magnetic recording medium according to claim 32 wherein a surface of said coating has a center line average height of 30 nm or less.

35. A magnetic recording medium according to claim 32 wherein said magnetic layer comprises a Co--Ni alloy.

36. A magnetic recording medium according to claim 32 wherein said magnetic layer comprises a metal.

37. A magnetic recording medium according to claim 32 wherein said coating comprises carbon including SP³ carbon bond and SP² carbon bond.

38. A magnetic recording medium according to claim 32 wherein concentration of said element selected from the group consisting of silicon, germanium, tin and lead is decreased toward a surface of said coating.

39. A magnetic recording medium according to claim 32 wherein said magnetic layer comprises CoPtCr.

40. A magnetic recording medium according to claim 32 wherein said magnetic layer comprises ferrite.

41. A magnetic recording medium comprising:

a substrate;

a coating comprising carbon including SP³ carbon bond provided over said substrate; and

a magnetic layer provided between said substrate and said coating,

wherein said coating contains hydrogen and an element selected from the group consisting of silicon, germanium, tin and lead.

42. A magnetic recording medium according to claim 41 wherein said coating contains 1 to 15% by atomic of silicon as said element.

43. A magnetic recording medium according to claim 41 wherein a surface of said coating has a center line average height of 30 nm or less.

44. A magnetic recording medium according to claim 41 wherein said magnetic layer comprises a Co--Ni alloy.

45. A magnetic recording medium according to claim 41 wherein said magnetic layer comprises a metal.

46. A magnetic recording medium according to claim 41 wherein said coating comprises carbon including SP³ carbon bond and SP² carbon bond.

47. A magnetic recording medium according to claim 41 wherein concentration of said element is decreased toward a surface of said coating.

48. A magnetic recording medium according to claim 41 wherein said magnetic layer comprises CoPtCr.

49. A magnetic recording medium according to claim 41 wherein said magnetic layer comprises ferrite.

50. A magnetic recording medium according to claim 41 wherein said coating contains hydrogen from 10 to 60% by atomic.

51. A magnetic recording medium comprising:

a substrate;

a coating comprising carbon including SP³ carbon bond provided over said substrate; and

a magnetic layer provided between said substrate and said coating,

wherein said coating contains an element selected from the group consisting of silicon, germanium, tin and lead, and

wherein said medium is one of an audio tape, a video tape, a floppy disk and a hard disk.

52. A magnetic recording medium according to claim 51 wherein said coating contains 1 to 15% by atomic of silicon as said element.

53. A magnetic recording medium according to claim 51 wherein a surface of said coating has a center line average height of 30 nm or less.

54. A magnetic recording medium according to claim 51 wherein said magnetic layer comprises a Co--Ni alloy.

55. A magnetic recording medium according to claim 51 wherein said magnetic layer comprises a metal.

56. A magnetic recording medium according to claim 51 wherein said coating comprises carbon including SP³ carbon bond and SP² carbon bond.

57. A magnetic recording medium according to claim 51 wherein concentration of said element is decreased toward a surface of said coating.

58. A magnetic recording medium according to claim 51 wherein said magnetic layer comprises CoPtCr.

59. A magnetic recording medium according to claim 51 wherein said magnetic layer comprises ferrite.

60. A magnetic recording medium according to claim 51 wherein said substrate comprises an organic material or a metal.

61. A magnetic recording medium comprising:

a substrate;

a coating comprising carbon including SP³ carbon bond provided over said substrate; and

a magnetic layer provided between said substrate and said coating,

wherein said coating comprises at least two layers, and a lowermost one of said at least two layers which is provided adjacent to said magnetic layer contains an element selected from the group consisting of silicon, germanium, tin and lead, and an uppermost one of said at least two layers contains no element selected from the group consisting of silicon, germanium, tin and lead.

62. A magnetic recording medium according to claim 61 wherein said lowermost one of said at least two layers contains 1 to 15% by atomic of silicon as said element.

63. A magnetic recording medium according to claim 61 wherein a surface of said coating has a center line average height of 30 nm or less.

64. A magnetic recording medium according to claim 61 wherein said magnetic layer comprises a Co--Ni alloy.

65. A magnetic recording medium according to claim 61 wherein said magnetic layer comprises a metal.

66. A magnetic recording medium according to claim 61 wherein said coating comprises carbon including SP³ carbon bond and SP² carbon bond.

67. A magnetic recording medium according to claim 61 wherein said magnetic layer comprises CoPtCr.

68. A magnetic recording medium according to claim 61 wherein said magnetic layer comprises ferrite.

69. A magnetic recording medium according to claim 61 wherein said substrate comprises an organic material or a metal.

70. A magnetic recording medium comprising:

a substrate;

a coating comprising carbon including SP³ carbon bond provided over said substrate; and

a magnetic layer provided between said substrate and said coating,

wherein said coating comprises at least two layers, and a lowermost one of said at least two layers which is provided adjacent to said magnetic layer contains an element selected from the group consisting of silicon, germanium, tin and lead, and an uppermost one of said at least two layers contains no element selected from the group consisting of silicon, germanium, tin and lead, and

wherein said coating contains hydrogen.

71. A magnetic recording medium according to claim 70 wherein said coating contains 1 to 15% by atomic of silicon as said element.

72. A magnetic recording medium according to claim 70 wherein a surface of said coating has a center line average height of 30 nm or less.

73. A magnetic recording medium according to claim 70 wherein said magnetic layer comprises a Co--Ni alloy.

74. A magnetic recording medium according to claim 70 wherein said magnetic layer comprises a metal.

75. A magnetic recording medium according to claim 70 wherein said coating comprises carbon including SP³ carbon bond and SP² carbon bond.

76. A magnetic recording medium according to claim 70 wherein said magnetic layer comprises CoPtCr.

77. A magnetic recording medium according to claim 70 wherein said magnetic layer comprises ferrite.

78. A magnetic recording medium according to claim 70 wherein said substrate comprises an organic material or a metal.

79. A magnetic recording medium according to claim 70 wherein said coating contains hydrogen from 10 to 60% by atomic.

80. A magnetic recording medium comprising;

a substrate;

a coating comprising carbon including SP³ carbon bond provided over said substrate; and

a magnetic layer provided between said substrate and said coating,

wherein said coating comprises at least two layers, and a lowermost one of said at least two layers which is provided adjacent to said magnetic layer contains an element selected from the group consisting of silicon, germanium, tin and lead, and

wherein said coating contains an element selected from the group consisting of boron, aluminum, gallium, nitrogen, phosphorus and arsenic.

81. A magnetic recording medium according to claim 80 wherein said coating contains 1 to 15% by atomic of silicon.

82. A magnetic recording medium according to claim 80 wherein a surface of said coating has a center line average height of 30 nm or less.

83. A magnetic recording medium according to claim 80 wherein said magnetic layer comprises a Co--Ni alloy.

84. A magnetic recording medium according to claim 80 wherein said magnetic layer comprises a metal.

85. A magnetic recording medium according to claim 80 wherein said coating comprises carbon including SP³ carbon bond and SP² carbon bond.

86. A magnetic recording medium according to claim 80 wherein said magnetic layer comprises CoPtCr.

87. A magnetic recording medium according to claim 80 wherein said magnetic layer comprises ferrite.

88. A magnetic recording medium according to claim 80 wherein said substrate comprises an organic material or a metal.

89. A magnetic recording medium comprising:

a substrate;

a coating comprising carbon including SP³ carbon bond provided over said substrate; and

a magnetic layer provided between said substrate and said coating,

wherein said coating comprises at least two layers, and a lowermost one of said at least two layers which is provided adjacent to said magnetic layer contains an element selected from the group consisting of silicon, germanium, tin and lead, and an uppermost one of said at least two layers contains no element selected from the group consisting of silicon, germanium, tin and lead, and

wherein said medium is one of an audio tape, a video tape, a floppy disk and a hard disk.

90. A magnetic recording medium according to claim 89 wherein said coating contains 1 to 15% by atomic of silicon as said element.

91. A magnetic recording medium according to claim 89 wherein a surface of said coating has a center line average height of 30 nm or less.

92. A magnetic recording medium according to claim 89 wherein said magnetic layer comprises a Co--Ni alloy.

93. A magnetic recording medium according to claim 89 wherein said magnetic layer comprises a metal.

94. A magnetic recording medium according to claim 89 wherein said coating comprises carbon including SP³ carbon bond and SP² carbon bond.

95. A magnetic recording medium according to claim 89 wherein said magnetic layer comprises CoPtCr.

96. A magnetic recording medium according to claim 89 wherein said magnetic layer comprises ferrite.

97. A magnetic recording medium according to claim 89 wherein said substrate comprises an organic material or a metal.