Abstract: A magnetic recording disk has a magnetic recording layer that includes a ferromagnetic host layer and a ferromagnetic overlay deposited directly on the host layer with an effective overlay thickness in the range of 1-40 Angstroms. The ferromagnetic material used in the overlay contains Co, Fe and/or Ni and has a magnetic moment significantly greater than that of the material in the ferromagnetic host layer. The ferromagnetic overlays improve the thermal stability of superparamagnetic grains contained within the host layers by magnetically coupling the grains through bridging. The enhanced thermal stability of the media allows for the use of thinner ferromagnetic host layers, and leads to lower remanent magnetization-thickness product (Mrt) values and higher recording densities.

Abstract: A magnetic recording disk has a magnetic recording layer formed on a special multilayered “host” layer. The host layer is a “synthetic antiferromagnetically”, i.e., at least two ferromagnetic films that are exchange-coupled antiferromagnetically (AF) to one another across a nonferromagnetic spacer film so that their magnetic moments are oriented antiparallel. The magnetic recording layer has a different composition from the top ferromagnetic film in the host layer and is ferromagnetically coupled to the top ferromagnetic film of the host layer. The magnetic volume V of the composite structure (magnetic recording layer and host layer) that determines the thermal stability will be approximately the sum of the volumes of the grains in the magnetic recording layer and the AF-coupled ferromagnetic films of the host layer.

Abstract: A improved thin film recording medium with an underlayer with deliberately induced strain, crystalline defects and dislocations (collectively “faults”) in the grain structure is described. The relatively high number of induced faults results in surprising improvements in recording characteristics such as soft error rate, resolution and SNR of the thin film disk. While the film is being deposited, the sputtering conditions are controlled to grow grains of the underlayer material which tend to be highly faulted by incorporation of atoms of a second material with significantly different atomic characteristics than the underlayer material. Preferably the atoms of the sputtering gas species are incorporated in the film to cause the lattice faults. For example, the faults can be achieved by incorporating sputtering gas atoms, e.g. argon atoms, into a chromium based underlayer.

Abstract: A magnetic layer structure with a layer of cobalt-chromium-platinum-boron composite alloy containing 10% to 20% B in the magnetic layer. The useful magnetic properties of the magnetic layer structure are achieved by the incorporation of a nucleation layer prior to the deposition of the magnetic layer. The resultant magnetic layer structures have coercivity Hc values in between 2,000 and 5,000 Oe, grain sizes between 30 and 200 Angstroms and anisotropic crystallographic orientation with the c-axis of the cobalt-chromium-platinum-boron in the plane of the medium. These magnetic layer structures are suitable for magnetic data storage devices including magnetic disks.

Abstract: A new method for making patterned magnetic storage media with magnetic and substantially non-magnetic zones utilizes a selective oxidation processes. Selective oxidation is achieved by subjecting a magnetic layer to an oxygen plasma through voids in a patterned mask. A high resolution patterned mask is made by embossing and reactive ion etch processes. The method is used to fabricate patterned magnetic disks media with alternating magnetic and non-magnetic zones ranging from 10 to 1000 Nanometers in width. Magnetic storage disks produced by this method have high-bit densities, minimal topography and reduced signal noise.

Abstract: A thin film disk and a disk drive using the thin film disk are described. The disk has a thin film magnetic layer composed of small acicular grains having an average aspect ratio greater than one which results in improved recording performance. The development of the acicularity is aided through the crystal structure having anisotropic inplane stress with a radial stress being less than a tangential stress. The preferred magnetic material is an alloy cobalt which includes a glass forming material such as boron, boron oxide, silicon, silicon oxide, carbon, phosphorus, etc. The typical hcp unit cells form acicular grains with a tendency for the C-axis to be orthogonal to a long axis of the acicular grains. Preferably the C-axis of the grains is oriented along the circumferential direction of the disk. Preferably the underlayer is sputtered deposited using negative bias.