Abstract:
A method of forming a uniform thickness layer of a selected material on a surface of a substrate comprises steps of: (a) providing a multi-stage cathode sputtering apparatus comprising a group of spaced-apart cathode/target assemblies and a means for transporting at least one substrate/workpiece past each cathode/target assembly, each cathode/target assembly comprising a sputtering surface oriented substantially parallel to the first surface of the substrate during transport past the group of cathode/target assemblies, the group of cathode/target assemblies adapted for providing different angular sputtered film thickness profiles; and (b) transporting the substrate past each cathode/target assembly while providing different sputtered film thickness profiles from at least some of the cathode/target assemblies, such that a plurality of sub-layers is deposited on the surface of the substrate/workpiece which collectively form a uniform thickness layer of the selected material.
Abstract:
A stack including a crystallographic orientation interlayer, a magnetic zero layer disposed on the interlayer, and a magnetic recording layer disposed on the magnetic zero layer is disclosed. The magnetic zero layer is non-magnetic or has a saturation magnetic flux density (Bs) less than about 100 emu/cc. The magnetic zero layer and the magnetic layer include grains surrounded by a non-magnetic segregant. The magnetic zero layer provides a coherent interface between the interlayer and the magnetic layer with a lattice mismatch less than about 4%.
Abstract:
An alignment procedure to insure the proper and faithful reproduction of the automatic control loop SERial DAta (SERDA) instructions issued by the Pulse Amplitude and Timing COntrol Unit (PATCO). This reproduction takes place during high level, multipulsed, radio frequency energy transfer to the antenna system. The precise reproduction of the low level digital pulse shape and timing instructions will insure that the transmitter set is operating within the constraints of the International Telecommunications Union for radio transmissions and the specifications which govern the original design during "automatic operation" at a specified Envelope to Cycle Difference (ECD). The alignment procedure once accomplished allows for a simplified monitoring technique, to insure continued proper operation. This monitoring and correction routine can be accomplished using personnel of less technical expertise and test equipments of less complexity and cost.
Abstract:
Various magnetic stack embodiments may be constructed with a soft magnetic underlayer (SUL) having a first thickness disposed between a substrate and a magnetic recording layer. A heatsink may have a second thickness and be disposed between the SUL and the magnetic recording layer. The first and second thicknesses may each be tuned to provide predetermined thermal conductivity and magnetic permeability throughout the data media.
Abstract:
Various magnetic slack embodiments may be constructed with a soft magnetic underlayer (SUL) having a first thickness disposed between a substrate and a magnetic recording layer. A heatsink may have a second thickness and be disposed between the SUL and the magnetic recording layer. The first and second thicknesses may each be tuned to provide predetermined thermal conductivity and magnetic permeability throughout the data media.
Abstract:
A perpendicular magnetic recording medium, comprising: (a) a non-magnetic substrate having a surface; and (b) a layer stack formed over the substrate surface, comprising in overlying sequence from the substrate surface: (i) a magnetically soft underlayer; (ii) an interlayer structure for crystallographically orienting a layer of a perpendicular magnetic recording material formed thereon; and (iii) at least one crystallographically oriented magnetically hard perpendicular recording layer; wherein the magnetically soft underlayer is sputter-deposited at a sufficiently large target-to-substrate spacing and at a sufficiently low gas pressure selected to provide the underlayer with a smooth surface having a low average surface roughness Ra below about 0.3 nm, as measured by Atomic Force Microscopy (AFM).
Abstract:
A stack including a crystallographic orientation interlayer, a magnetic zero layer disposed on the interlayer, and a magnetic recording layer disposed on the magnetic zero layer is disclosed. The magnetic zero layer is non-magnetic or has a saturation magnetic flux density (Bs) less than about 100 emu/cc. The magnetic zero layer and the magnetic layer include grains surrounded by a non-magnetic segregant. The magnetic zero layer provides a coherent interface between the interlayer and the magnetic layer with a lattice mismatch less than about 4%.
Abstract:
A perpendicular magnetic recording system, comprises: a perpendicular magnetic recording medium including a non-magnetic substrate having a surface and a stacked plurality of thin film layers forming a layer stack overlying the substrate surface and including a magnetically soft underlayer (SUL) beneath at least one perpendicular magnetic recording layer, wherein the SUL has a saturation magnetization (Ms)—thickness (t) product (Mst) less than about 4 memu/cm2, and a ring-type magnetic transducer head is positioned in spaced adjacency to an upper surface of the layer stack.
Abstract:
Methods and media structures are provided for increasing writability and reducing unintentional erasure of perpendicular magnetic recording media. Variable permeability is controlled within a thin soft underlayer (SUL) structure, independent of bulk SUL material properties such as magnetic moment (Bs) and magnetic anisotropy (Hk). Media with an improved combination of easier writability on the recorded track and difficult erasure off-track (between tracks and on neighboring tracks) is achieved, in part, by an unbalanced antiferromagnetically coupled (AFC) SUL structure. A permeability gradient is established within the soft underlayer with layers having different values of permeability and magnetic thickness (Bs*t). In an aspect, a first SUL layer includes a high permeability region and an overlying low permeability region. A second layer antiferromagnetically couples the first layer to a low permeability third SUL layer. The present invention may be utilized with high density perpendicular recording media requiring carefully balanced magnetic properties.
Abstract:
Methods and media structures are provided for increasing writability and reducing unintentional erasure of perpendicular magnetic recording media. Variable permeability is controlled within a thin soft underlayer (SUL) structure, independent of bulk SUL material properties such as magnetic moment (Bs) and magnetic anisotropy (Hk). Media with an improved combination of easier writability on the recorded track and difficult erasure off-track (between tracks and on neighboring tracks) is achieved, in part, by an unbalanced antiferromagnetically coupled (AFC) SUL structure. A permeability gradient is established within the soft underlayer with layers having different values of permeability and magnetic thickness (Bs*t). In an aspect, a first SUL layer includes a high permeability region and an overlying low permeability region. A second layer antiferromagnetically couples the first layer to a low permeability third SUL layer. The present invention may be utilized with high density perpendicular recording media requiring carefully balanced magnetic properties.