Hitachi, Ltd.

Hitachi Global Storage Technologies Netherlands B.v.

Hitachi-lg Data Storage, Inc.

Hitachi Consumer Electronics Co., Ltd.

Kimio Nakamura

Takuya Matsumoto

Hiroaki Nemoto

Hirofumi Sukeda

Hideki Saga

Yohji Maruyama

Sumio Hosaka

Takehiko Hamaguchi

Hiroshi Ide

Masahiko Takahashi

Fumiko Akagi

Hiroshi Suzuki

Kenchi Ito

Yasushi Miyauchi

Koichi Watanabe

Toshimichi Shintani

Yoshio Takahashi

Masaru Muranishi

Ryo Imura

Ikuko Takekuma

Tomokazu Shimakura

Junichi Sayama

Surface flatness of magnetic recording medium to which a magnetic recording layer made of L1FePt magnetic alloy thin film, with distance between a magnetic head and a magnetic recording medium sufficiently reduced. The magnetic recording layer includes: magnetic layers containing a magnetic alloy including Fe and Pt as principal materials; and one non-magnetic material selected from carbon, oxide and nitride. The first magnetic layer disposed closer to a substrate has a granular structure in which magnetic alloy grains including FePt alloy as the principal material are separated from grain boundaries including the non-magnetic material as the principal material. The second magnetic layer disposed closer to the surface than the first magnetic layer is fabricated so as to have a homogeneous structure in which an FePt alloy and the non-magnetic material are mixed in a state finer than diameters of the FePt magnetic alloy grains in the first magnetic layer.

Magnetic recording medium including plural FePt alloy layers including carbon, oxides or nitrides

To solve the problem of deterioration in recording quality due to a change of a write waveform caused by changes of temperature and recording powers, aged deterioration and the like. A driver having a function of controlling rise/fall times and an overshoot amount of an optical waveform is used to optimize an optical waveform that changes in recording under the influence of a component of a laser and the like. Specifically, the rise/fall times and the overshoot amount of the optical waveform are optimized by obtaining a waveform control register value from test recording or a table.

Optical information recording method

Embodiments of the present invention help to suppress the effects of thermal fluctuation in a thermally assisted magnetic field recording, and improve recording density. According to one embodiment, a recording area of a magnetic disk is heated and the full width at half maximum of an optical power distribution of a near field light generator is controlled to be 100 nm or less. Thereby, the cooling time of the magnetic disk is made 2 nm or less and the effects of thermal fluctuation are suppressed. Moreover, although an incomplete area of the magnetization reversal at the rear end of the magnetic domain is created with rapid cooling, by creating an overshoot at the rising end of the magnetic field waveform of the magnetic recording head, the incomplete area of the magnetization reversal can be overwritten, which is created at the rear end of the magnetic domain previously recorded by the overshoot magnetic field. Therefore, the expansion of the magnetic transition width can be suppressed, resulting in the recording density being improved.

Thermally assisted magnetic recording head, recording system, and recording method

To reduce background light generated in a circumference of a scatterer in a head for a thermally assisted magnetic recording device using a scatterer having conductivity as an optical near-field generating element, a coil for generating a magnetic field is placed on a bottom portion of a slider, and an optical near-field generating element is placed in an inside of the coil. At this time, an inner diameter of the coil is set not larger than a wavelength of incident light, an interval between leader lines each for conducting an electric current to the coil is set not larger than a half of the wavelength of the light, and the coil for generating the magnetic field is caused to function as a shield for suppressing the background light.

Head for thermally assisted magnetic recording device and thermally assisted magnetic recording device

Heating power control is performed in thermally assisted magnetic recording using a patterned recording medium. Trial writing is performed by continuously changing a heating power intensity with respect to a pattern row of a trial writing area provided in plurality on the recording medium. From a reproduction signal thereof, a minimum heating power of recording that is a boundary power between recording and non-recording, and a maximum heating power of recording that is a boundary power between recording and a heating power by which recorded information of an adjacent pattern is deleted are determined to decide an optimum recording power.

Thermally assisted magnetic recording system and thermally assisted magnetic recording

In order to prevent deterioration of floating characteristics of a slider due to deformation of a slider floating surface by thermal expansion of a coil, the followings are performed. A recessed portion is formed in a part of the slider, and a device for generating an optical near-field and the coil for generating a magnetic field are formed in the recessed portion. The optical near-field generation device is formed on a surface facing a recording medium, and the magnetic field application coil is formed on an upper surface of the recessed portion. The optical near-field generation device and the magnetic field application coil are respectively exposed to the surface.

Thermally assisted magnetic recording head and method of manufacturing the same

The optimum head-field intensity for saturation recording is assumed to be 560&#xd7;10A/m or more. Under a condition where the recording track width of an information recording medium is equal to or less than 60 nm, the optimum head-field intensity Y satisfies the following inequalities (1) and (2):&#x2267;(&#x2212;119&#xd7;+4135)&#xd7;1000&#x2003;&#x2003;(1)&#x2266;(&#x2212;119&#xd7;+const)&#xd7;1000&#x2003;&#x2003;(2)where X denotes the nondimensional value of the recording track width divided by 10m, and Y denotes a magnetic field (expressed in units of A/m) which a magnetic pole for head-field application applies to the center of the information recording medium in the direction of the thickness thereof. Note that const=&#x2212;0.8&#xd7;v+33.7&#xd7;v+4250 if the relative velocity v between the head and the medium at the position of the head is less than 20 m/sec, or const=4600 if the velocity v is equal to or more than 20 m/sec.

Thermally assisted magnetic recording system

A magnetic recording apparatus suitable for high-density and high-frequency magnetic recording includes a recording head to the coil of which a recording current is supplied, the recording current having a waveform such that the conducting time length is shorter than the time length of a recording pattern.

Magnetic recording apparatus and system for driving a magnetic recording medium

A method and instrument for measuring, with a high spatial resolution, a magnetic or electric field that varies repeatedly at high speed. An electron beam is deflected by passage through a magnetic or electric field to be measured and is allowed to pass through a deflection electrode to thereby be deflected in a direction perpendicular to the magnetic or electric field to be measured. A track of the deflected electron beam is detected by a two-dimensional sensor, and a waveform or pattern is displayed wherein a time base and an axis of the magnetic field to be measured are orthogonal to each other.

Method and instrument for measuring a magnetic field, a method for measuring a current waveform, and method for measuring an electric field

A method for reproducing information on a recording medium includes irradiating electromagnetic energy or light to the recording medium from one side with respect to the recording medium, applying a recording magnetic field to an electromagnetic energy or light irradiated position on the recording medium from the one side of irradiating electromagnetic energy or light, and detecting magnetic leakage flux emerging from the recording medium from the one side of irradiating electromagnetic energy or light.

Method for reproducing information on a recording medium

An information recording apparatus using a recording medium which holds information by reversed magnetic domains on a perpendicular magnetic recording film includes an irradiation unit for applying electromagnetic energy or light onto the recording medium, and a magnetic flux detection unit for detecting magnetic leakage flux emerging from the recording medium, the magnetic flux detection unit being disposed on the same side as the irradiation unit with respect to the recording medium. As a result, both side recording of the recording medium can be conducted.

Information recording/reproducing device

A pad for controlling the state of contact or flying of a slider with or to an information-recording medium and a probe for exciting near-field light having a small spot size are mounted on the slider and the pad is near to the probe. Semiconductor laser light focused by an objective lens is converted into near-field light having a small spot size near the top of the probe for exciting near-field light. The slider travels at a height of several tens nm to a recording medium substrate and information is recorded or read out on or from the information-recording medium formed on the recording medium substrate.

Near-field optical head and manufacturing method thereof and optical recording/readout system using near-field optical head

An information recording and reproducing apparatus includes an optical head having a super resolution film formed therein. The optical head includes a laser for producing an energy beam, a lens for focusing the energy beam and a super resolution film disposed in a position on which the energy beams is focused by the lens, whereby recording and reproducing of high-density information is attained.

Information recording and reproducing apparatus and methods of recording and reproducing information using solid immersion lens having super resolution film deposited thereon

An information recording apparatus having a light generator for emitting light as a signal of information being recorded, a probe formed of an optical fiber for physically or chemically changing a recording medium on the basis of the light, a slider coupled to the probe and maintaining the distance between the tip of the optical fiber and the recording medium to be within the radius of an aperture provided at the tip of the optical fiber when recording is made, a medium support for supporting the recording medium, and a medium driving mechanism for driving the recording medium to move.

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Fujisawa, Japan

Kimio Nakamura