Abstract: A manufacturing method for a magnetic recording medium is disclosed. By using the method, the anisotropic magnetic field (Hk) of an underlayer is improved, spike noise generated in the soft magnetic underlayer is suppressed, and the signal-to-noise ratio (SNR) is improved without employing a special layer configuration and without the need for complicated and expensive processing. A soft magnetic underlayer is formed by laminating a soft magnetic lower underlayer, a non-magnetic metal layer, and a soft magnetic upper underlayer in succession on a non-magnetic substrate. After forming the non-magnetic metal layer, its surface is exposed to a gas containing between 2 and 100 at % oxygen. A perpendicular magnetic recording layer is formed on the soft magnetic underlayer.

Abstract: A perpendicular magnetic recording medium is disclosed. The formation of a domain wall in a soft magnetic backing layer relative to a large external magnetic field can be suppressed better in the medium, the Hk of the backing layer is improved, and productivity can be increased. The perpendicular magnetic recording medium is formed by laminating at least a soft magnetic backing layer, a non-magnetic underlayer, a magnetic recording layer, and a protective film in succession on a non-magnetic substrate. The backing layer, underlayer, magnetic recording layer, and protective film are formed by a vapor deposition method. The backing layer is a laminated body with a soft magnetic lower backing layer, non-magnetic metal layer, and soft magnetic upper backing layer. The non-magnetic metal layer is formed by forming a metal layer and then subjecting the metal layer to surface exposure processing using a nitrogen-containing gas containing 0.1 to 100 at % nitrogen.

Abstract: A magnetic recording medium exhibiting low noise and having a sufficiently high coercive force includes a magnetic layer having a granular structure including ferromagnetic crystal grains with a hexagonal closed packed structure and a nonmagnetic grain boundary region of mainly an oxide intervening between the crystal grains. An underlayer has a body-centered cubic lattice structure. A nonmagnetic intermediate layer with the hexagonal closest packed structure includes Ru, Os, and/or Re, which are provided between the magnetic layer and the underlayer. A degree of mismatching ?=|d1?d2|/d1 is at most 10%, for instance, in a range from 2.5% to 7.0%, where d1 is a spacing of lattice planes of the crystal grains in the magnetic layer and d2 is a spacing of the lattice planes of the crystal grains in the intermediate layer.

Abstract: A magnetic recording medium has a non-magnetic under-layer, a magnetic layer, a protective film and a liquid lubricant layer sequentially laminated on a non-magnetic substrate. The magnetic layer has a multi-layer structure laminated with two or more magnetic layer components, each of the magnetic layer components having ferromagnetic grains and non-magnetic grain boundaries surrounding the grain. The resulting magnetic recording medium has a granular magnetic layer exhibiting very high Hc accompanying high density of magnetic recording, while decreasing the amount of platinum needed for attaining the high Hc, and reducing media noise accompanying the high recording density.

Abstract: A magnetic recording medium for perpendicular magnetic recording system includes a nonmagnetic substrate and layers sequentially laminated on the substrate. The layers include a seed layer comprised of a metal or an alloy with a face centered cubic crystal structure, a nonmagnetic underlayer of a metal or an alloy with a hexagonal closest packed crystal structure, a magnetic layer having a granular structure including ferromagnetic crystalline grains with a hexagonal closest packed structure and nonmagnetic grain boundary region of mainly oxide surrounding the crystalline grains, a protective layer, and a liquid lubricant layer.

Abstract: The quantity of oxide contained in a magnetic layer is controlled to control the crystal grains and the segregation structure for ensuring low noise characteristic in a granular magnetic layer of a perpendicular magnetic recording medium. The granular magnetic layer consists of ferromagnetic crystal grains and a nonmagnetic grain boundary region mainly of an oxide surrounding the ferromagnetic crystal grains. The perpendicular magnetic recording medium has a nonmagnetic underlayer composed of a metal or alloy having hexagonal closest-packed crystal structure. The ferromagnetic crystal grain is composed of an alloy containing at least cobalt and platinum. The volume proportion of the nonmagnetic grain boundary region mainly of the oxide falls within a range of 15% to 40% of the volume of the total magnetic layer.

Abstract: A magnetic recording medium for perpendicular magnetic recording system includes a nonmagnetic substrate and layers sequentially laminated on the substrate. The layers include a seed layer comprised of a metal or an alloy with a face centered cubic crystal structure, a nonmagnetic underlayer of a metal or an alloy with a hexagonal closest packed crystal structure, a magnetic layer having a granular structure including ferromagnetic crystalline grains with a hexagonal closest packed structure and nonmagnetic grain boundary region of mainly oxide surrounding the crystalline grains, a protective layer, and a liquid lubricant layer.

Abstract: A nonmagnetic foundation layer is made to have a body-centered cubic crystal structure with a preferred crystal orientation plane being the bcc (110) plane. A nonmagnetic intermediate layer, provided between the foundation layer and a granular magnetic layer, has a hexagonal close-packed structure with the hcp (100) plane or the hcp (200) plane being the preferred orientation plane. Furthermore, the crystal lattice misfit amount between the nonmagnetic intermediate layer 3 and the granular magnetic layer is made to be not more than 10% for each of an a-axis and a c-axis. As a result, epitaxial growth of ferromagnetic crystals in the granular magnetic layer, which has an hcp structure, is promoted, and hence the crystallinity of the magnetic layer is increased, and thus it becomes possible to simultaneously realize an increase in coercivity and a reduction in noise. Depositing the layers on an unheated substrate yields reduces manufacturing costs.

Abstract: The quantity of oxide contained in a magnetic layer is controlled to control the crystal grains and the segregation structure for ensuring low noise characteristic in a granular magnetic layer of a perpendicular magnetic recording medium. The granular magnetic layer consists of ferromagnetic crystal grains and a nonmagnetic grain boundary region mainly of an oxide surrounding the ferromagnetic crystal grains. The perpendicular magnetic recording medium has a nonmagnetic underlayer composed of a metal or alloy having hexagonal closest-packed crystal structure. The ferromagnetic crystal grain is composed of an alloy containing at least cobalt and platinum. The volume proportion of the nonmagnetic grain boundary region mainly of the oxide falls within a range of 15% to 40% of the volume of the total magnetic layer.

Abstract: A perpendicular magnetic recording medium has a granular magnetic layer and a nonmagnetic underlayer of a metal or an alloy having a hexagonal close packed (hcp) crystal structure. A seed layer of a metal or an alloy of a face-centered cubic (fcc) crystal structure is provided under the nonmagnetic underlayer. Such a perpendicular magnetic recording medium exhibits excellent magnetic characteristics even when the thickness of the underlayer or the total thickness of the underlayer and the seed layer is very thin. Excellent magnetic characteristics can be obtained even when of the substrate is not preheated. Accordingly, a nonmagnetic substrate, such as a plastic resin can be employed to reduce the manufacturing cost.

Abstract: A magnetic recording medium and a manufacturing method therefore includes a protective film, a nonmagnetic substrate, a nonmagnetic base layer, a nonmagnetic intermediate layer, a magnetic layer, and a liquid lubricant layer. The nonmagnetic base layer has a body-centered cubic structure and a (200) plane including a crystal-orientation parallel with a surface of the protective film. The nonmagnetic intermediate layer has a hexagonal close-packed structure and a (110) plane including a crystal-orientation parallel with the surface of the protective film. The magnetic layer has a granular structure including hexagonal close-packed ferromagnetic crystal grains and oxide-based nonmagnetic grain boundaries surrounding the ferromagnetic crystal grains. The nonmagnetic base layer, the nonmagnetic intermediate layer, the magnetic layer, the protective film, and the liquid lubricant layer are sequentially stacked on the nonmagnetic substrate.

Abstract: A magnetic recording medium, and method of manufacturing the same, is provided with excellent recording performance by employing a granular magnetic layer having a specified composition. A magnetic recording medium according to the present invention comprises a nonmagnetic underlayer, a granular magnetic layer, a protective film, and a liquid lubrication layer sequentially laminated on a nonmagnetic substrate. The granular magnetic layer consists of ferromagnetic crystal grains containing cobalt and nonmagnetic grain boundary region surrounding the ferromagnetic crystal grains. The ferromagnetic crystal grains contain platinum in the range of 15 at % to 17 at %.

Abstract: There is provided a perpendicular magnetic recording medium according to which both the thermal stability of the magnetization is good and writing with a magnetic head is easy, and moreover the SNR is improved. In the case of a perpendicular magnetic recording medium comprising a nonmagnetic substratel, and at least a nonmagnetic underlayer 2, a magnetic recording layer 3 and a protective layer 4 formed in this order on the nonmagnetic substrate 1, the magnetic recording layer 3 comprises a low Ku region 31 layer having a perpendicular magnetic anisotropy constant (Ku value) of not more than 1×105 erg/cm3, and a high Ku region 32 layer having a Ku value of at least 1×106 erg/cm3. Moreover, the magnetic recording layer 3 is made to have therein nonmagnetic grain boundaries that contain a nonmagnetic oxide and magnetically isolate crystal grains, which are made of a ferromagnetic metal, from one another.

Abstract: A magnetic recording medium, and method of manufacturing the same, is provided with excellent recording performance by employing a granular magnetic layer having a specified composition. A magnetic recording medium according to the present invention comprises a nonmagnetic underlayer, a granular magnetic layer, a protective film, and a liquid lubrication layer sequentially laminated on a nonmagnetic substrate. The granular magnetic layer consists of ferromagnetic crystal grains containing cobalt and nonmagnetic grain boundary region surrounding the ferromagnetic crystal grains. The ferromagnetic crystal grains contain platinum in the range of 15 at % to 17 at %.

Abstract: A perpendicular magnetic recording medium has a nonmagnetic substrate, a nonmagnetic underlayer, a magnetic layer, a protective film, and a liquid lubrication layer sequentially laminated on the substrate. The nonmagnetic layer is composed of a metal or alloy having a hcp crystal structure. The magnetic recording layer consists of ferromagnetic crystal grains and a nonmagnetic grain boundary phase mainly composed of an oxide surrounding the grains. A seed layer of a metal or alloy having a fcc crystal structure can be provided under the nonmagnetic underlayer, and a nonmagnetic alignment control layer can be provided under the seed layer. The recording medium can provide high output and low noise by improving the alignment of the magnetic recording layer, reducing the initial growth layer in the magnetic recording layer, and minimizing the grain size of the magnetic recording layer.

Abstract: A magnetic recording medium exhibits a high coercive force and suppresses noises caused therefrom at a low level. The magnetic recording medium includes a nonmagnetic substrate, a nonmagnetic undercoating layer on the substrate where the undercoating layer has a hexagonal close packing structure or a combination of the hexagonal close packing structure and a body center cubic structure. The magnetic recording medium includes a nonmagnetic intermediate layer on the undercoating layer, where the intermediate layer has a hexagonal close packing structure or a combination of the hexagonal close packing structure and a body center cubic structure, and a magnetic layer on the intermediate layer. The magnetic layer has a granular structure formed of ferromagnetic crystal grains and oxide grain boundaries or nitride grain boundaries surrounding the ferromagnetic crystal grains.

Abstract: A manufacturing method achieves excellent magnetic recording characteristics by sequentially sputtering a non-magnetic under-layer, a non-magnetic intermediate layer, and a magnetic layer on a non-magnetic substrate in an atmosphere of H2O partial pressure of 2×10−10 Torr or lower. This process allows beneficial deposition of the magnetic layer and reduces raw materials costs. The magnetic layer includes ferromagnetic grains and non-magnetic grain boundaries. The intermediate layer has a hexagonal close-packed crystal structure. The manufacturing method allows manufacture of a high quality magnetic recording medium without a heating step thereby allowing use of lower cost materials, reduces manufacturing time, and increases savings.

Abstract: A nonmagnetic foundation layer is made to have a body-centered cubic crystal structure with a preferred crystal orientation plane being the bcc (110) plane. A nonmagnetic intermediate layer, provided between the foundation layer and a granular magnetic layer, has a hexagonal close-packed structure with the hcp (100) plane or the hcp (200) plane being the preferred orientation plane. Furthermore, the crystal lattice misfit amount between the nonmagnetic intermediate layer 3 and the granular magnetic layer is made to be not more than 10% for each of an a-axis and a c-axis. As a result, epitaxial growth of ferromagnetic crystals in the granular magnetic layer, which has an hcp structure, is promoted, and hence the crystallinity of the magnetic layer is increased, and thus it becomes possible to simultaneously realize an increase in coercivity and a reduction in noise. Depositing the layers on an unheated substrate yields reduces manufacturing costs.

Abstract: A magnetic recording medium includes a magnetic recording layer composed of an L10 type ordered alloy at a low temperature. The magnetic recording layer of the L10 type ordered alloy exhibits high magnetic anisotropy energy Ku that is necessary for compatibility between improvement in thermal stability and reduction of noises. Specifically, the recording medium includes a nonmagnetic substrate, a nonmagnetic underlayer, a magnetic recording layer, a protective layer, and a liquid lubricant layer sequentially formed on the substrate. The magnetic recording layer is formed by alternately depositing an iron or cobalt layer having thickness in a range of 0.1 nm to 0.3 nm and a platinum layer having thickness of in a range of 0.15 nm to 0.35 nm repetitively. The magnetic recording layer is mainly composed of an alloy of FePt or CoPt that includes a region with an L10 type ordered structure.

Abstract: A perpendicular magnetic recording medium has a granular magnetic layer and a nonmagnetic underlayer of a metal or an alloy having a hexagonal closest-packed (hcp) crystal structure. A seed layer of a metal or an alloy of a face-centered cubic (fcc) crystal structure is provided under the nonmagnetic underlayer. Such a perpendicular magnetic recording medium exhibits excellent magnetic characteristics even when the thickness of the underlayer or the total thickness of the underlayer and the seed layer is very thin. Excellent magnetic characteristics can be obtained even when of the substrate is not preheated. Accordingly, a nonmagnetic substrate, such as a plastic resin can be employed to reduce the manufacturing cost.