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US 5,626,970 AGranted
Sputtered magnetic thin film recording disk
OwnerVirgle L. Hedgcothinventor
Life of this patent
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Abstract
The improved sputtered memory disk of the present invention comprises a substrate coated with a nucleating layer, a subsequent magnetic layer, and a protective coating. As a result of texturing in the circumferential direction and epitaxy involving the nucleating layer, an anisotropic orientation of coercivity in the circumferential direction has occurred during the sputtering that provides an improved memory disk having enhanced coercivity, a reduced amplitude modulation, an improved squareness of the hysteresis loop, e.g., lower switching field distribution, and a high production, relatively low cost production system. As a result, a higher recording density due to the higher coercivity and low switching field distribution can be experienced with the magnetic disk of the present invention.
Claims90
A magnetic thin film recording disk formed by a series of sequential sputtering processes within an environment of a low pressure inert gas, comprising:
- a substrate having a nickel phosphorous surface layer, the substrate including aluminum, the substrate characterized by a surface having texturing in a circumferential direction prior to any sputtering operation contributing to an anisotropic orientation of coercivity in the circumferential direction while not interfering with fly characteristics of a recording head across the recording disk, an Ra, arithmetic average radial roughness of the texturing contributing to a magnetic switching field distribution of less than 0.20;
- a thin film nucleating layer containing chromium, and substantially free of oxidation, deposited above the textured nickel phosphorous surface by a first sputtering process;
- a thin film magnetic layer containing a cobalt alloy deposited above the nucleating layer by a second sputtering process and having an anisotropic orientation of coercivity in the circumferential direction;
- and
- a thin film protective layer containing carbon deposited above the magnetic layer by a third sputtering process.
2 more elements
A magnetic thin film recording disk formed by a series of sequential sputtering processes within an environment of a low pressure inert gas, comprising:
- a substrate having a nickel phosphorous surface layer, the substrate including aluminum, the substrate characterized by a surface having texturing in a circumferential direction prior to any sputtering operation contributing to an anisotropic orientation of coercivity in the circumferential direction, while not interfering with fly characteristics of a recording head across the recording disk, an Ra, arithmetic average radial roughness of the texturing contributing to reduced amplitude modulation, any output of a signal recorded on the magnetic thin film recording disk will have an amplitude modulation, and the amplitude modulation will be less than 25 percent;
- a thin film nucleating layer containing chromium and substantially free of oxidation, deposited above the textured nickel phosphorous surface by a first sputtering process;
- a thin film magnetic layer containing a cobalt alloy deposited above the nucleating layer by a second sputtering process and having an anisotropic orientation of coercivity in the circumferential direction;
- and
- a thin film protective layer containing carbon deposited above the magnetic layer by a third sputtering process.
2 more elements
A magnetic thin film recording disk formed by a series of sequential sputtering processes within an environment of a low pressure inert gas, comprising:
- a substrate characterized by a surface having texturing in a circumferential direction prior to any sputtering operation contributing to an anisotropic orientation of coercivity in the circumferential direction, while not interfering with fly characteristics of a recording head across the recording disk, an Ra, arithmetic average radial roughness of the texturing contributing to a magnetic switching field distribution of less than 0.20, any output of a signal recorded on the magnetic thin film recording disk having an amplitude modulation, the amplitude modulation being less than 25 percent;
- a thin film nucleating layer, substantially free of oxidation, deposited above the textured substrate surface by a first sputtering process;
- a thin film magnetic layer containing a cobalt alloy deposited above the nucleating layer by a second sputtering process and having an anisotropic orientation of coercivity in the circumferential direction;
- and
- a thin film protective layer containing carbon deposited above the magnetic layer by a third sputtering process.
2 more elements
A magnetic thin film recording disk formed by a series of sequential sputtering processes within an environment of a low pressure inert gas, comprising:
- a substrate characterized by a surface having texturing in a circumferential direction prior to any sputtering operation to encourage a circular anisotropic orientation of crystal growth during sputtering, while not interfering with fly characteristics of a recording head across the recording disk, an Ra, arithmetic average radial roughness of circumferential texturing contributing to a magnetic switching field distribution of less than 0.20;
- a thin film nucleating layer deposited above the textured surface by a first sputtering process;
- a thin film magnetic layer deposited above the nucleating layer by a second sputtering process and having an anisotropic orientation of coercivity in the circumferential direction;
- and
- a thin film protective layer deposited above the magnetic layer by a third sputtering process.
2 more elements
A magnetic thin film recording disk formed by a series of sequential sputtering processes within an environment of a low pressure inert gas, comprising:
- a substrate characterized by a surface having texturing in a circumferential direction prior to any sputtering operation to encourage a circular anisotropic orientation of crystal growth during sputtering, while not interfering with fly characteristics of a recording head across the recording disk, an Ra, arithmetic average radial roughness of circumferential texturing contributing to reduced amplitude modulation such that any output of a signal recorded on the magnetic thin film recording disk will have an amplitude modulation, and the amplitude modulation will be less than 25 percent;
- a thin film nucleating layer deposited above the textured surface by a first sputtering process;
- a thin film magnetic layer deposited above the nucleating layer by a second sputtering process and having an anisotropic orientation of coercivity in the circumferential direction;
- and
- a thin film protective layer deposited above the magnetic layer by a third sputtering process.
2 more elements
A magnetic thin film recording disk formed by a series of sequential sputtering processes within an environment of a low pressure inert gas, comprising:
- a substrate characterized by a surface having a texturing in a circumferential direction prior to any sputtering operation to encourage a circular anisotropic orientation of crystal growth during sputtering, while not interfering with fly characteristics of a recording head across the recording disk, an Ra, arithmetic average radial roughness of the texturing contributing to a magnetic switching field distribution of less than 0.20, any output of a signal recorded on the magnetic thin film recording disk having an amplitude modulation, the amplitude modulation being less than 25 percent;
- a thin film nucleating layer deposited above the textured substrate surface by a first sputtering process;
- a thin film magnetic layer containing a cobalt alloy deposited above the nucleating layer by a second sputtering process and having an anisotropic orientation of coercivity in the circumferential direction;
- and
- a thin film protective layer deposited above the magnetic layer by a third sputtering process.
2 more elements
A magnetic thin film recording disk formed by a series of sequential sputtering processes within an environment of a low pressure inert gas, comprising:
- a substrate having a nickel phosphorous layer, the substrate characterized by a surface having texturing in a circumferential direction prior to any sputtering operation to encourage a circular anisotropic orientation of crystal growth during sputtering, while not interfering with fly characteristics of a recording head across the recording disk, an Ra, arithmetic average radial roughness of a circumferential texturing of the finished disk being in a range of 0.18 microinches to 0.6 microinches for contributing to a magnetic switching field distribution of less than 0.20;
- a thin film nucleating layer containing chromium deposited above the textured nickel phosphorous surface by a first sputtering process;
- a thin film magnetic layer containing a cobalt alloy deposited above the nucleating layer by a second sputtering process and having an anisotropic orientation of coercivity in the circumferential direction;
- and
- a thin film protective layer containing carbon deposited above the magnetic layer by a third sputtering process.
2 more elements
A magnetic thin film recording disk formed by a series of sequential sputtering processes within an environment of a low pressure inert gas, comprising:
- a glass substrate being characterized by a surface having texturing in a circumferential direction prior to any sputtering operation to encourage a circular anisotropic orientation of crystal growth during sputtering, while not interfering with fly characteristics of a recording head across the recording disk, an Ra, arithmetic average radial roughness of the circumferential texturing of the finished disk contributing to a magnetic switching field distribution of less than 0.20;
- a nucleating layer deposited above the textured glass surface by a first sputtering process;
- a magnetic layer containing a cobalt alloy deposited above the nucleating layer by a second sputtering process and having an anisotropic orientation of coercivity in the circumferential direction;
- and
- a protective layer containing carbon deposited above the magnetic layer by a third sputtering process.
2 more elements
The magnetic thin film recording disk of claim 45 wherein the temperature of the substrate is heated to a temperature within a range of 200.degree. C. to 250.degree. C.
A magnetic thin film recording disk formed by a series of sequential sputtering processes within an environment of a low pressure inert gas, comprising:
- a glass substrate being characterized by a surface having texturing in a circumferential direction prior to any sputtering operation contributing to an anisotropic orientation of coercivity in the circumferential direction during sputtering, while not interfering with fly characteristics of a recording head across the recording disk, an Ra, arithmetic average radial roughness of the circumferential texturing of the finished disk contributing to a magnetic switching field distribution of less than 0.20;
- a nucleating layer, substantially free of oxidation, deposited above the textured glass surface by a first sputtering process;
- a magnetic layer containing a cobalt alloy deposited above the nucleating layer by a second sputtering process and having an anisotropic orientation of coercivity in the circumferential direction;
- and
- a protective layer containing carbon deposited above the magnetic layer by a third sputtering process.
2 more elements
A magnetic thin film recording disk formed by a series of sequential sputtering processes within a continuous production environment of a low pressure inert gas, comprising:
- a substrate characterized by a surface having texturing in a circumferential direction prior to any sputtering operation contributing to an anisotropic orientation of coercivity in the circumferential direction while not interfering with fly characteristics of a recording head across the recording disk;
- a thin film nucleating layer deposited above the substrate by a first sputtering process;
- a thin film magnetic layer containing a hexagonal close-packed cobalt alloy deposited over the nucleating layer by a second sputtering process and having an anisotropic orientation of coercivity in the circumferential direction;
- and
- a thin film protective layer containing carbon deposited above the magnetic layer by a third sputtering process.
2 more elements
A magnetic thin film recording disk formed by a series of sequential sputtering processes within an environment of a low pressure inert gas, comprising:
- a substrate having a nonmagnetic surface layer, the substrate including aluminum, the substrate characterized by a surface having texturing in a circumferential direction prior to any sputtering operation contributing to an anisotropic orientation of coercivity in the circumferential direction while not interfering with fly characteristics of a recording head across the recording disk,
- a thin film nucleating layer deposited above the textured surface by a first sputtering process;
- a thin film magnetic layer containing a hexagonal closed packed cobalt alloy deposited above the nucleating layer by a second sputtering process and having an anisotropic orientation of coercivity in the circumferential direction;
- and
- a thin film protective layer containing carbon deposited above the magnetic layer by a third sputtering process.
2 more elements
A magnetic thin film recording disk formed by a series of sequential sputtering processes within an environment of a low pressure inert gas, comprising:
- a substrate characterized by a surface having texturing in a circumferential direction prior to any sputtering operation contributing to an anisotropic orientation of coercivity in the circumferential direction while not interfering with fly characteristics of a recording head across the recording disk,
- a thin film nucleating layer, substantially free of oxidation, deposited above the textured surface by a first sputtering process;
- a thin film magnetic layer, substantially free of oxidation, deposited above the nucleating layer by a second sputtering process and having an anisotropic orientation of coercivity in the circumferential direction;
- and
- a thin film protective layer deposited above the magnetic layer by a third sputtering process.
2 more elements
A magnetic thin film recording disk formed by a series of sequential sputtering processes within an environment of a low pressure inert gas, comprising:
- a substrate having a nickel phosphorous surface layer, the substrate including aluminum, the substrate characterized by a surface having texturing in a circumferential direction prior to any sputtering operation contributing to an anisotropic orientation of coercivity in the circumferential direction while not interfering with fly characteristics of a recording head across the recording disk;
- a thin film nucleating layer containing chromium, substantially free of oxidation, deposited over the textured nickel phosphorous surface by a first sputtering process;
- a thin film magnetic layer containing a hexagonal close-packed cobalt alloy deposited over the nucleating layer by a second sputtering process and having an anisotropic orientation of coercivity in the circumferential direction;
- and
- a thin film protective layer containing carbon deposited over the magnetic layer by a third sputtering process.
2 more elements
A magnetic thin film recording disk formed by a series of sequential sputtering processes within an environment of a low pressure inert gas, comprising:
- a substrate characterized by a surface having texturing prior to any sputtering operation contributing to an anisotropic orientation of coercivity in the circumferential direction while not interfering with fly characteristics of a recording head across the recording disk;
- a thin film nucleating layer, substantially free of oxidation, deposited above the textured surface by a first sputtering process;
- a thin film magnetic layer, substantially free of oxidation, deposited above the nucleating layer by a second sputtering process and having an anisotropic orientation of coercivity in the circumferential direction;
- and
- a thin film protective layer deposited above the magnetic layer by a third sputtering process.
2 more elements
A magnetic thin film recording disk formed by a series of sequential sputtering processes within an environment of a low pressure inert gas, comprising:
- a substrate having a nickel phosphorous surface layer, the substrate including aluminum, the substrate characterized by a surface having texturing prior to any sputtering operation contributing to an anisotropic orientation of coercivity in the circumferential direction while not interfering with fly characteristics of a recording head across the recording disk;
- a thin film nucleating layer containing chromium, substantially free of oxidation, deposited over the textured nickel phosphorous surface by a first sputtering process;
- a thin film magnetic layer containing a hexagonal close-packed cobalt alloy deposited over the nucleating layer by a second sputtering process and having an anisotropic orientation of coercivity in the circumferential direction;
- and
- a thin film protective layer containing carbon deposited over the magnetic layer by a third sputtering process.
2 more elements
Dependencies are inferred from the claim text.