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Hiroaki Nemoto

Hiroaki Nemoto, Odawara JP

Patent application numberDescriptionPublished
20100110576THERMALLY ASSISTED RECORDING MEDIA AND SYSTEM - A thermally assisted magnetic recording medium includes a substrate and at least two, i.e., first and second magnetic recording layers. These layers are hard magnetic layers and contain magnetic grains and a non-magnetic substance magnetically segregating the magnetic grains at grain boundaries. The first magnetic recording layer has a magnetic anisotropy energy K05-06-2010
20110020669MAGNETIC RECORDING MEDIUM - A magnetic recording medium having excellent stability of recorded magnetic signals and capable of recording magnetic signals by a thermally assisted magnetic recording system in which a magnetic recording layer of the magnetic recording medium contains ferromagnetic crystal grains of a Co—Ni—Pt alloy with a Pt content of 44 at % or more and 55 at % or less and with an atom content ratio: Ni/(Co+Ni) of 0.64 or more and 0.8 or less. The magnetic recording medium has extremely excellent stability of recorded magnetic signals since the Co—Ni—Pt alloy constituting the magnetic recording layer has an extremely high anisotropy field at a normal temperature. Further, the magnetic recording medium can perform signal recording based on the thermally assisted magnetic recording system since the Co—Ni—Pt alloy constituting the magnetic recording layer has a Curie point within an appropriate temperature range.01-27-2011

Hiroaki Nemoto, Kokubunji-Shi JP

Patent application numberDescriptionPublished
20100188769METHOD AND DEVICE FOR INFORMATION RECORDING/REPRODUCING AND INFORMATION RECORDING MEDIUM - In an information recording/reproducing method performing a thermo-magnetic recording, a tracking offset value of a recording light spot and/or a tracking offset value of a magnetic flux detecting element is changed in accordance with a radial position at which a tracking is performed at the present time, to make a direction of a magnetic wall of a recording magnetic domain in accord with a longitudinal direction of the magnetic flux detecting element. Alternatively, a shape of a heated area is changed to be in accord with the direction of the magnetic flux detecting means at respective radial position, to make the direction of the magnetic wall of the recording magnetic domain in accord with the longitudinal direction of the magnetic flux detecting element.07-29-2010

Hiroaki Nemoto, Kanagawa JP

Patent application numberDescriptionPublished
20090073599Perpendicular magnetic recording medium and magnetic recording and reproducing apparatus using the same - Embodiments of the present invention provide a perpendicular magnetic recording medium suitable for high density recording. According to one embodiment, a magnetic recording layer comprises four layers in which a first magnetic layer, a magnetic coupling layer, a second magnetic layer, and a third magnetic layer are formed above a substrate. The first magnetic layer and the second magnetic layer are perpendicular magnetization films containing an oxide, and ferromagnetically coupled with each other by way of the magnetic coupling layer, and they are, more preferably, a Co alloy layer containing an oxide. The third magnetic layer is ferromagnetically coupled with the second magnetic layer. The concentration of the oxide contained in the third magnetic layer is lower than the concentration of the oxide in the second recording layer, or the third magnetic layer does not contain the oxide. In this case, magnetic property is set for the anisotropic magnetic field Hk1 of the first magnetic layer and the anisotropic magnetic field Hk2 of the second magnetic layer, so as to satisfy: Hk1>Hk2.03-19-2009
20090116137Perpendicular magnetic recording medium and magnetic storage apparatus using the same - Embodiments of the present invention provide a perpendicular magnetic recoding medium capable of decreasing exchange coupling between crystal grains while suppressing increase in the crystal grain size of the magnetic recording layer. According to one embodiment, a perpendicular magnetic recoding medium is formed by stacking a seed layer, an intermediate layer, a magnetic recording layer, and a protecting layer all above a substrate. The magnetic recording layer has a granular structure constituted of a plurality of columnar grains comprising a CoCrPt alloy and a grain boundary containing an oxide. The seed layer is formed by stacking a first seed layer, a second seed layer, and a third seed layer in which the first seed layer comprises Ti or Ti alloy having a hexagonal close-packed structure, the second seed layer comprises Cu, Ag, or Al having a face-centered cubic structure or an alloy containing at least one element selected therefrom, and the third seed layer comprises an Ni alloy having a face-centered cubic structure.05-07-2009
20090195924Perpendicular magnetic recording medium and magnetic recording/reproducing apparatus using the same - Embodiments of the present invention help allow accurate control of the magnetization reversal in a magnetic recording layer in small reversal units, whereby high-density recording can be achieved. According to one embodiment, by forming an intermediate layer having a granular structure similar to that of the magnetic recording layer below the magnetic recording layer, a continuous crystal grain boundary is formed at the interface between the magnetic recording layer and the intermediate layer, thereby preventing incomplete formation of the crystal grain boundary found in the initial growth layer of the magnetic recording layer. The intermediate layer comprises a non-magnetic alloy comprising Co and Cr as its main components and an oxide such as Al, Cr, Hf. Mg, Nb, Si, Ta, Ti and Zr. Further, the average content of the oxygen element in the intermediate layer is in the range from 6 at % to 20 at %.08-06-2009
20100142084MAGNETIC MEDIUM HAVING AN ARTIFICIAL PATTERN STRUCTURE USING A GRADIENT OF A MAGNETIZATION REVERSAL FIELD AND A METHOD OF USE THEREOF - To avoid the occurrence of a recording error by suppressing the influence that a magneto-static interaction acting between the pattern dots exerts on a recording process and expand a margin for recording synchronization timing lag or tracking misregistration on the pattern dot. Each pattern dot has a structure in which a plurality of parts having different magnetization reversal fields are bonded with exchange interaction in the in-plane direction of a medium, substrate. The positional relationship between the parts having different magnetization reversal Fields is substantially coincident between the adjacent pattern dots, which are arranged to have a gradient of magnetization reversal field in a track direction or track transverse direction. Further, the recording is performed by adapting a gradient of recording magnetic field to the gradient of magnetization reversal field. Other methods and systems are described as well.06-10-2010
20100165500Thermal Energy Assisted Medium - In order to provide a thermal energy assisted medium capable of improving anti-sliding reliability over long periods of time in low flying head conditions, while also maintaining a high SNR, a unique medium is proposed. A soft magnetic layer is formed on a substrate, a soft magnetic layer is formed thereon via a non-magnetic intermediate layer, and an intermediate layer, a crystal oriented control intermediate layer, an artificial lattice intermediate layer having an artificial lattice film in which a first layer comprising Co and a second layer comprising Pt and Pd are laminated repeatedly to form a recording layer, and a cap layer and an lubricating layer are formed. The concentration of Pd comprising the second layer is from about 20 atomic % to about 40 atomic %. Other mediums and systems are also described.07-01-2010

Patent applications by Hiroaki Nemoto, Kanagawa JP

Hiroaki Nemoto, Odawara-Shi JP

Patent application numberDescriptionPublished
20110122525MAGNETIC RECORDING MEDIUM USING LAYERS HAVING HIGHER- AND LOWER-HK ANISOTROPIC MAGNETIC FIELDS - According to one embodiment, a magnetic recording medium includes a magnetic recording layer formed above a substrate, comprising: a first magnetic layer formed from a [Co/Pt]05-26-2011