Abstract: Embodiments of the invention prevent demagnetization or degaussing of recorded magnetizations, even if a stray field is applied. In one embodiment, an output of a read head including a magneto-resistive effect element is inputted to a stray field detector through a DC amplifier and a DC filter. The stray field detector monitors dc components of the output from the read head, and escapes a head from above a magnetic recording medium.

Abstract: Embodiments in accordance with the invention realize a perpendicular magnetic record medium with a high media S/N and excellent corrosion resistance. In a perpendicular magnetic record medium in accordance with an embodiment of the present invention prepared by forming an adhesion layer, an underlayer, a seed layer, an intermediate layer, and a recording layer sequentially on a substrate, the seed layer is specified to have a laminated structure consisting of a first seed layer and a second seed layer. The first seed layer consists of an amorphous alloy containing Cr and the second seed layer consists of an amorphous alloy predominantly composed of Ni with an fcc structure.

Abstract: A magnetic recording/reproducing apparatus is disclosed with high storage capability. The apparatus also prevents fluctuation of readback output and decay of magnetization or erasure of recorded magnetization in the recording layer. A soft magnetic underlayer and a perpendicular recording layer are formed in specific order on the substrate of a magnetic disk. The soft magnetic underlayer has a triple-layered structure in which a domain control layer, including an anti-ferromagnetic layer, is sandwiched between two first and second soft magnetic layers. The thickness of the first and second soft magnetic layers (d1, d2) is between 25 nm and 150 nm and a ratio of d1/d2 is within a range of 0.3 to 1.5. Accordingly, magnetic domains in the soft magnetic underlayer of a perpendicular magnetic recording medium can be controlled and magnetic domain wall motion can be inhibited.

Abstract: A medium having high medium S/N and excellent corrosion resistance is achieved. In one embodiment, an adhesion layer, a soft magnetic layer, an intermediate layer, a magnetic recording layer, and a protective layer are deposited, in order, on a substrate. The soft magnetic underlayer consists at least of two soft magnetic layers, the first soft magnetic layer formed on the recording layer side being composed of an amorphous alloy containing 85 at. % or less of Co, and the second soft magnetic layer formed on the substrate side being composed of an alloy containing more than 85 at. % of Co.

Abstract: A soft magnetic underlayer includes a first amorphous soft magnetic layer to which an exchange bias magnetic field is applied directly from an antiferromagnetic layer or via a ferromagnetic layer, and a second amorphous soft magnetic layer which is formed on the first amorphous soft magnetic layer via a non-magnetic layer. The first amorphous soft magnetic layer and the second amorphous soft magnetic layer are antiferromagnetically coupled.

Abstract: A magnetoresistive sensor of the type of flowing a signal sensing current perpendicular to the plane, a magnetic head using the magnetoresistive sensor, and a magnetic disk apparatus, comprising a substrate, a pair of magnetic shield layers consisting of a lower magnetic shield layer and an upper magnetic shield layer, a magnetoresistive sensor layer, disposed between the pair of magnetic shield layers, an electrode terminal for flowing a signal current perpendicular to the plane of the magnetoresistive sensor layer, and magnetic domain control layers for controlling Barkhausen noise of the magnetoresistive sensor layer, the magnetic domain control layers being disposed in contact with opposite ends of the magnetoresistive sensor layer consist of a material having high electric resistivity and with a specific resistance not less than 10 m?cm.

Abstract: Embodiments of the invention provide a medium which provides high media S/N and good corrosion resistance. According to one embodiment, in a perpendicular magnetic recording medium at least comprising a soft-magnetic underlayer, a seed layer, an intermediate layer, a magnetic recording layer and an overcoat layer which are stacked over a substrate in order, the magnetic recording layer has a granular structure which consists of many columnar grains of CoCrPt alloy and a grain boundary layer containing an oxide, the seed layer is made of TaNi alloy or TaTi alloy and the intermediate layer is made of Ru or Ru alloy which contains about 80 at. % Ru or more.

Abstract: Embodiments of the invention are directed to a medium which provides high media S/N and good corrosion resistance. According to one embodiment, in a perpendicular magnetic recording medium at least comprising a soft-magnetic underlayer, a seed layer, an intermediate layer, a magnetic recording layer and an overcoat layer which are stacked over a substrate in order, the magnetic recording layer has a granular structure which includes many columnar grains of CoCrPt alloy and a grain boundary layer containing an oxide, the seed layer is made of TaNi alloy or TaTi alloy and the intermediate layer is made of Ru or Ru alloy which contains 80 at. % Ru or more.

Abstract: Embodiments of the invention relate to easily achieving a perpendicular magnetic recording medium with high reliability and a magnetic recording apparatus with high recording density by improving the magnetic properties and surface smoothness of the soft magnetic underlayer and, moreover, enhancing adhesion with the substrate.

Abstract: Embodiments of the invention prevent demagnetization or degaussing of recorded magnetizations, even if a stray field is applied. In one embodiment, an output of a read head including a magneto-resistive effect element is inputted to a stray field detector through a DC amplifier and a DC filter. The stray field detector monitors dc components of the output from the read head, and escapes a head from above a magnetic recording medium.

Abstract: A magnetoresistive sensor of the type of flowing a signal sensing current perpendicular to the plane, a magnetic head using the magnetoresistive sensor, and a magnetic disk apparatus, comprising a substrate, a pair of magnetic shield layers consisting of a lower magnetic shield layer and an upper magnetic shield layer, a magnetoresistive sensor layer, disposed between the pair of magnetic shield layers, an electrode terminal for flowing a signal current perpendicular to the plane of the magnetoresistive sensor layer, and magnetic domain control layers for controlling Barkhausen noise of the magnetoresistive sensor layer, the magnetic domain control layers being disposed in contact with opposite ends of the magnetoresistive sensor layer consist of a material having high electric resistivity and with a specific resistance not less than 10 m?cm.

Abstract: Embodiments of the invention provide a perpendicular magnetic recording medium improved for fly ability, high in read signal quality, and capable of suppressing magnetic decay of recorded magnetization to be caused by stray fields. In one embodiment, a perpendicular recording layer is formed over a substrate with a soft magnetic underlayer therebetween, then an amorphous or nano-crystalline layer is formed between the substrate and the soft magnetic underlayer. The soft magnetic underlayer includes first and second amorphous soft magnetic layers, as well as a nomnagnetic layer formed between those first and second amorphous soft magnetic layers. The first and second amorphous soft magnetic layers are given uniaxial anisotropy in the radial direction of the substrate respectively and coupled with each other antiferromagnetically.

Abstract: There are provided a magnetoresistive sensor of the type of flowing a signal sensing current perpendicular to the plane to improve resolution at reproducing a signal, a magnetic head using the magnetoresistive sensor, and a magnetic disk apparatus.

Abstract: A magnetoresistive sensor of the type of flowing a signal sensing current perpendicular to the plane to improve resolution at reproducing a signal, a magnetic head using the magnetoresistive sensor, and a magnetic disk apparatus. A magnetoresistive sensor comprising a substrate, a pair of magnetic shield layers consisting of a lower magnetic shield layer and an upper magnetic shield layer, a magnetoresistive sensor layer, disposed between the pair of magnetic shield layers, an electrode terminal for flowing a signal current perpendicular to the plane of the magnetoresistive sensor layer, and magnetic domain control layers for controlling Barkhausen noise of the magnetoresistive sensor layer, wherein the magnetic domain control layers disposed in contact with opposite ends of the magnetoresistive sensor layer consist of a material having high electric resistivity and with a specific resistance not less than 10 m?cm so as to give the magnetoresistive sensor having excellent reproducing resolution.

Abstract: A soft magnetic underlayer includes a first amorphous soft magnetic layer to which an exchange bias magnetic field is applied directly from an antiferromagnetic layer or via a ferromagnetic layer, and a second amorphous soft magnetic layer which is formed on the first amorphous soft magnetic layer via a non-magnetic layer. The first amorphous soft magnetic layer and the second amorphous soft magnetic layer are antiferromagnetically coupled.

Abstract: This invention provides a magnetic recording/reproducing apparatus with high storage capability and an areal recording density over 7.75 Gbits/cm2, in which fluctuation of readback output and decay of magnetization or erasure of recorded magnetization in the recording layer are prevented. On the substrate of a magnetic disk, a soft magnetic underlayer and a perpendicular recording layer are formed in order, where the soft magnetic underlayer has a triple-layered structure in which a domain control layer including an anti-ferromagnetic layer is sandwiched between two first and second soft magnetic layers. Given that thickness of the first soft magnetic layer is d1 and thickness of the second soft magnetic layer is d2, d1 and d2 should be between 25 nm and 150 nm and a ratio of d1/d2 should fall within a range of 0.3 to 1.5. Thereby, magnetic domains in the soft magnetic underlayer of a perpendicular magnetic recording medium are controlled and magnetic domain wall motion can be inhibited.

Abstract: There are provided a magnetoresistive sensor of the type of flowing a signal sensing current perpendicular to the plane to improve resolution at reproducing a signal, a magnetic head using the magnetoresistive sensor, and a magnetic disk apparatus.

Abstract: The invention provides a magnetoresistive effect sensor that is a yoke type magnetoresistive effect sensor having a tunnel magnetoresistive effect film, which is operated stably with suppressed Barkhausen noise, and provides a reproducing head and a magnetic disk apparatus that use the magnetoresistive effect sensor. The magnetoresistive effect sensor is provided with a tunnel magnetoresistive effect film, a pair of electrodes for supplying a current in the film thickness direction of the magnetoresistive effect film, and a magnetic flux guide for guiding a magnetic flux from the recording medium: surface to the magnetoresistive effect film, wherein the magnetic domain of a free layer of the tunnel type magnetoresistive effect film and the magnetic domain of the magnetic flux guide are both controllable together.

Abstract: The invention provides a magnetoresistive effect sensor that is a yoke type magnetoresistive effect sensor having a tunnel magnetoresistive effect film, which is operated stably with suppressed Barkhausen noise, and provides a reproducing head and a magnetic disk apparatus that use the magnetoresistive effect sensor. The magnetoresistive effect sensor is provided with a tunnel magnetoresistive effect film, a pair of electrodes for supplying a current in the film thickness direction of the magnetoresistive effect film, and a magnetic flux guide for guiding a magnetic flux from the recording medium surface to the magnetoresistive effect film, wherein the magnetic domain of a free layer of the tunnel type magnetoresistive effect film and the magnetic domain of the magnetic flux guide are both controllable together.

Abstract: A magnetoresistive sensor employing a magnetoresistive sensor film of a GMR film or a TMR film and a magnetic flux guide to ensure high sensitivity and high stability. Magnetization of a magnetic flux guide and a first ferromagnetic layer, which is a free layer of a GMR sensor film or a TMR sensor film, are made to antiferromagnetically couple to each other via a nonmagnetic intermediate layer 21. Since net magnetic moment has become small in the area in which the magnetoresistive sensor film is arranged, and an angle of magnetization of the ferromagnetic layer rotated by magnetic field which has been guided by the magnetic flux guide enlarges, high sensitivity can be obtained. When a longitudinal biasing layer is provide for the magnetic flux guide, longitudinal biasing magnetic field is applied to the ferromagnetic layer as well which is antiferromagnetically coupled to the magnetic flux guide, thus being able to suppress Barkhausen noise of both the magnetic flux guide and the ferromagnetic layer.