Claims
- 1. A magnetic recording medium, comprising a substrate and a crystalline longitudinal magnetic recording layer having longitudinal magnetic anisotropy formed on the substrate, said magnetic recording layer having a composition of:
- Co.sub.1-x-y Pt.sub.x Cr.sub.y, (0.15<x.ltoreq.0.35; 0<y.ltoreq.0.15)
- and containing at least one of oxygen and nitrogen in a concentration less than 2.5.times.10.sup.21 atom/cm.sup.3 and greater than 0.9.times.10.sup.21 atom/cm.sup.3 ; and
- wherein a squareness ratio of said magnetic layer is greater than 0.65.
- 2. The magnetic recording medium according to claim 1, wherein the oxygen and/or nitrogen content in the magnetic layer is 0.7 to 1.5.times.10.sup.21 atom/cm.sup.3.
- 3. The magnetic recording medium according to claim 1, wherein the Cr content y in the magnetic layer is 0.05<y.ltoreq.0.15.
- 4. A magnetic recording medium according to claim 1, wherein said magnetic layer contains nitrogen in a concentration of less than 2.5.times.10.sup.21 atom/cm.sup.3 and greater than 0.9.times.10.sup.21 atom/cm.sup.3.
- 5. A magnetic recording medium according to claim 1, wherein:
- said substrate is non-magnetic and said magnetic layer is in contact with said non-magnetic substrate.
- 6. A method of manufacturing a longitudinal type crystalline recording medium, comprising the step of forming on a substrate a longitudinally anisotropic magnetic layer having a composition of:
- Co.sub.1-x-y Pt.sub.x Cr.sub.y, (0.15<x.ltoreq.0.35; 0<y.ltoreq.0.15)
- said magnetic layer being formed by sputtering method under an inert gas atmosphere containing 0.1 to 10% by volume of at least one of N.sub.2 and O.sub.2, wherein a squareness ratio of said magnetic layer is greater than 0.65.
- 7. The method according to claim 6, wherein the N.sub.2 and/or O.sub.2 content in the atmosphere is 1 to 10% by volume.
- 8. The method according to claim 6, wherein the Cr content y in the magnetic layer is 0.05<y.ltoreq.0.15.
- 9. The method according to claim 6, wherein the pressure of the inert gas atmosphere is 0.1 to 3 Pa.
- 10. A magnetic recording medium, comprising a substrate and a crystalline longitudinal magnetic recording layer having longitudinal anisotropy formed on the substrate, the magnetic recording layer having a composition of:
- Co.sub.1-x-y Pt.sub.x Cr.sub.y, (0.15<x.ltoreq.0.35; 0<y.ltoreq.0.15)
- and containing at least one of oxygen and nitrogen in a concentration of less than 2.5.times.10.sup.21 atom/cm.sup.3 and greater than 0.9.times.10.sup.21 atom/cm.sup.3 ; and
- wherein the magnetic recording layer has a squareness ratio of greater than 0.5.
- 11. A magnetic recording medium according to claim 10, wherein the magnetic recording layer has a coercivity of greater than 500 Oersted.
- 12. A magnetic recording medium according to claim 10, wherein the magnetic recording layer contains nitrogen in a concentration of less than 2.5.times.10.sup.21 atom/cm.sup.3 and greater than 0.9.times.10.sup.21 atom/cm.sup.3.
- 13. A magnetic recording medium according to claim 10, wherein the substrate is non-magnetic and the magnetic recording medium is in contact with a surface of said non-magnetic substrate.
- 14. A magnetic recording medium according to claim 10, wherein y=0.03 and x=0.2.
- 15. A magnetic recording medium according to claim 10, wherein y=0.10 and x=0.18.
- 16. A magnetic recording medium according to claim 10, wherein y=0.05.
- 17. A magnetic recording medium according to claim 10, wherein y=0.1 and x=0.2.
- 18. A magnetic recording medium according to claim 10, wherein the magnetic recording layer has a thickness of about 500 .ANG..
- 19. A magnetic recording medium according to claim 10, wherein the magnetic recording layer has a coercivity of greater than 900 Oersted.
- 20. A magnetic recording medium according to claim 13, wherein said surface of the substrate has a composition selected from a member of the group consisting of glass, polyimide, and NiP.
Priority Claims (2)
Number |
Date |
Country |
Kind |
1-177564 |
Jul 1989 |
JPX |
|
1-328243 |
Dec 1989 |
JPX |
|
Parent Case Info
This application is a continuation of application Ser. No. 07/914,009, filed on Jul. 14, 1992, now abandoned, which is a continuation of Ser. No. 07/549,918, filed on Jul. 9, 1990, also abandoned.
US Referenced Citations (10)
Foreign Referenced Citations (8)
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61-276115 |
Jan 1985 |
JPX |
61-194635 |
Feb 1985 |
JPX |
61-242321 |
Apr 1985 |
JPX |
61-246914 |
Apr 1985 |
JPX |
61-250827 |
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61-253622 |
Apr 1985 |
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6247818 |
Aug 1985 |
JPX |
63-187414 |
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JPX |
Non-Patent Literature Citations (2)
Entry |
Journal of Applied Physics, vol. 53, No. 10, p. 6941; "Effect of Nitrogen on the High Coercivity and Microstructures of Co-Ni Alloy Films"; Oct. 1982. |
Journal of Applied Physics, vol. 53, No. 8; p. 3263; "The Effect of Cr and W Nucleation Layers on the Magnetic Properties of CoPt Films"; Howard; Apr. 15, 1988. |
Continuations (2)
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Number |
Date |
Country |
Parent |
914009 |
Jul 1992 |
|
Parent |
549918 |
Jul 1990 |
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