Hitachi Maxell, Limited

Masaki Sekine

Hiroyuki Awano

Masafumi Yoshihiro

Manabu Tani

Norio Ohta

Hideo Daimon

Kohei Ugawa

Nobuyuki Inaba

Fumiyoshi Kirino

Katsusuke Shimazaki

Teruaki Takeuchi

Satoshi Matsunuma

Kouichirou Wakabayashi

Akira Yano

Hiroki Takao

Katsuji Nakagawa

Yuji Yamazaki

Tetsunori Koda

Harumi Hieida

Akiyoshi Itou

Yukiko Yamamoto

Hiroshi Ido

A fuel cell has an anode, a cathode, and a polymer electrolyte membrane placed between the anode and the cathode. The anode includes a catalyst which is composed of binary or ternary particulates deposited on a carbon support. The particulate is represented by a general formula: Pt&#x2014;P, wherein Ru is optionally present. The content of P is in a range of 2 mol % to 50 mol % based on the total moles of Pt or Pt&#x2014;Ru. The diameter of the catalyst particulates is in range from 1 to 3 nm.

Fuel cell and membrane electrode assembly

A fuel cell includes a fuel electrode, an oxygen electrode, and a polymer electrolyte membrane placed between the fuel electrode and the oxygen electrode. The fuel electrode and/or the oxygen electrode include a catalyst composed of a particle containing at least Pt and P and a carbon support.

Fuel cell, membrane electrode assembly, catalyst used therefor, and method of producing catalyst

A magnetic recording medium comprises an information-recording film and a ferromagnetic film on a substrate. The information-recording film is composed of, for example, an amorphous ferrimagnetic material having perpendicular magnetization. Further, the ferromagnetic film is composed of a magnetic material which has saturation magnetization larger than that of the information-recording film. Accordingly, the leak magnetic flux from the ferromagnetic film is larger than that from the information-recording film. The magnetic recording medium and a magnetic recording apparatus are obtained, which are excellent in thermal stability and which are preferred to perform super high density recording.

Magnetic recording medium with high thermal stability, method for producing the same, and magnetic recording apparatus

While a magneto-optical recording medium is irradiated with a laser beam, the medium is rotated relative to the beam at a controlled speed in such a manner that a high temperature region of a heat spot produced on the basis of the light intensity distribution of the beam is formed outside the associated light spot. A magnetic field source includes a magnetic field generator which is narrow in the direction along the track of the medium. The field source is positioned with the field generator at the heat center outside the light spot to apply a narrow recording magnetic field to the high temperature region. This forms a recording magnetic domain in the high temperature region. The magnetic domain is rectangular and narrow in the direction along the track. Rectangular recording magnetic domains adjoining in the direction along the track hardly interfere with each other even if they are closely spaced. This results in high density recording.

Recording method, reproducing method and recording and reproducing apparatus for magneto-optical recording medium

A recording method for recording information on a recording layer of a magneto optical recording medium by radiating a recording light beam onto the medium while applying a magnetic field in a recording direction to the medium. The method includes applying a magnetic field having a magnetic field strength H1 in the recording direction when recording a record mark having a mark length A on the recording layer, and applying a magnetic field have a magnetic field strength H2 in the recording direction when recording a record mark having a mark length B (B&ne;A) on the recording layer. Independent of the lengths of the magnetic domains recorded on the recording layer, the record information can be transferred to a reproducing layer making it possible to reproduce high density record information.

Magneto-optical recording apparatus using multiple magnetic field strengths for recording different mark lengths

Disclosed are a reproducing method and a reproducing apparatus capable of performing reproduction with a wide power margin, as well as a recording method and a recording apparatus preferably used for super high density recording. A recording and reproducing apparatus principally comprises a magnetic field-applying unit, a laser beam-radiating section, and a signal processing system. A magnetic coil which is provided for the magnetic field-applying unit, is arranged so that its axis of magnetic field generation is oblique to a surface of an information-recording medium A reproducing magnetic field is applied in an oblique direction to the surface of the information-recording medium by using the magnetic coil while radiating a reproducing light beam to the medium by using the laser beam-radiating section. Accordingly, the leak magnetic field in the in-plane direction from a recording magnetic domain in a recording layer is amplified. The inversion of magnetization in a reproducing layer tends to occur, and the reproducing power margin is widened. The recording and reproducing apparatus is also capable of recording information. An extremely minute recording magnetic domain can be formed in the recording layer of the information-recording medium.

METHOD AND APPARATUS FOR RECORDING AND REPRODUCING INFORMATION BY APPLYING FIELD IN A DIRECTION OTHER THAN THE DIRECTION OF MAGNETIZATION OR THE DIRECTION TO A SURFACE OF AN INFORMATION RECORDING MEDIUM

The magneto-optical recording medium has a magnetic domain magnification reproducing layer and an information recording layer. Clock marks are formed on the information recording layer, making it possible to generate a reproducing clock on the basis of these. The clock marks are detected either by irradiating directly with light of wavelength &lgr; (&lgr; &ne;&lgr; ), being different from the light of wavelength &lgr; which is used for reproducing the recording marks, or by applying a direct-current magnetic field, transferring and enlarging the clock marks on to the magnetic domain magnification reproducing layer, and detecting the reproduction signals from this magnetic domain magnification reproducing layer. Since the reproducing clock is in exact synchronisation with the recording marks, it is eminently suitable as a clock for pulse-modulated reproducing light and reproducing magnetic fields used when reproducing the reproducing layer.

Magneto-optical recording medium having clock-marks on recording layer and apparatus for recording and reproducing same

A bit of binary information which is one of &ldquo;1&rdquo; and &ldquo;0&rdquo; is assigned to a domain pattern which is a combination of a recorded magnetic domain and a magnetic domain magnetized in the direction opposite to the direction in which the recording domain is magnetized. A bit of binary information which is the other of &ldquo;1&rdquo; and &ldquo;0&rdquo; is assigned to a domain pattern consisting of two magnetic domains magnetized in the same direction as the foregoing magnetic domain is magnetized. Consequently, two or more consecutive bits of record information are formed, on a recording layer, as a series of domain patterns each of which is a combination, as a record information unit, of a recorded magnetic domain and a magnetic domain magnetized in the direction opposite to the direction in which the recording domain is magnetized. Independent of the lengths of the magnetic domains recorded on the recording layer, the record information can be transferred to a reproducing layer. This makes it possible to reproduce high-density record information securely or reliably.

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Ibaraki, Japan

Masaki Sekine