Sharp Kabushiki Kaisha Corporation

Kunio Kojima

Shigemi Maeda

Shigeo Terashima

Hiroshi Fuji

Toshihisa Deguchi

Takeshi Yamaguchi

Hiroyuki Katayama

Yasushi Ogimoto

Tomiyuki Numata

Junichi Sato

Masaki Hamamoto

Jun Akiyama

Shintaro Miyanishi

Noriaki Sakamoto

Yoshihiro Sekimoto

Masaru Nomura

Nobuo Ogata

Tsuneo Fujiwara

Kenji Ohta

Kenji Nakanishi

Tomoyuki Miyake

Yasuo Nakata

Takashi Iwaki

Shinzo Sawamura

Kentaro Tsuji

Kosuke Watanabe

Hirotsugu Matoba

Naoyasu Iketani

Hideaki Sato

Toshiharu Inui

Daiji Yamane

Akira Takahashi

Yoshiteru Murakami

Junichiro Nakayama

Mototaka Taneya

Takeshi Hashimoto

Toshihiro Yamanaka

Satoru Ariyoshi

Nobuyuki Horie

Mamoru Oda

Atsushi Yamanaka

Yoshihiro Yamamoto

Kentaroh Tsuji

Tadashi Une

Kensuke Goto

Yoshihiko Minamiyama

Shigema Maeda

Kazuaki Okumura

Kazuhisa Takayama

Junichi Satoh

Examples of an electromagnetic field detecting element according to the present invention includes a substrate, a pair of electrodes, three insulation layers disposed on the substrate and between the electrodes. The three insulation layers are designed to have two or three different dielectric breakdown strength. At least two ballistic current paths are formed between the electrodes. With this structure, it is possible to perform at a room temperature a highly efficient electromagnetic field detection utilizing Aharonov-Bohm effect or Aharonov-Casher effect.

Electromagnetic field detecting element utilizing ballistic current paths

An electromagnetic field generating element restrains magnetic field attenuation or magnetic field delay in a high frequency recording/reproducing head for thermally assisted magnetic field recording/reproduction using a near field. An information recording/reproducing head and an information recording/reproducing apparatus carry out high frequency magnetic recording/reproduction. The electromagnetic field generating element includes: (i) a substrate, (ii) conductors each provided on the substrate and each serving as a supporting section, (iii) a plate-like-shaped conductor provided on the conductors and (iv) a semiconductor laser element provided on the substrate. The semiconductor laser element irradiates laser light to the plate-like-shaped conductor substantially parallel to an extending flat surface of the plate-like-shaped conductor. This causes generation of a near field in the plate-like-shaped conductor. In addition, a magnetic field is generated by supplying a current to the plate-like-shaped conductor.

Electromagnetic field generating element, information recording/reproducing head and information recording/reproduction apparatus

Electromagnetic field generating element, information recording/reproducing head, and information recording/reproducing apparatus

To suppress a magnetic wall movement in the structure including an amorphous magnetic layer as a recording layer, and to realize a high density recording with a sufficient signal quality level, a magnetic recording medium includes an amorphous magnetic layer (recording layer) formed on a substrate, a non-magnetic metal element layer (underlayer) formed between the substrate and the amorphous magnetic layer, wherein an average surface roughness Ra of the non-magnetic metal element layer is in a range of 0.7 nm to 2.0 nm. The foregoing structure having the non-magnetic metal element layer of a large average surface roughness Ra brings about a great pinning effect onto the amorphous magnetic layer, thereby forming magnetic bits under stable conditions when carrying out a high density recording.

Magnetic recording medium, magnetic recording device, and method of manufacturing magnetic recording medium

To realize an electromagnetic field generating element, an information recording and reproducing head and an information recording and reproducing device for high frequency magnetic recording and reproducing by the optically assisted magnetic recording and reproduction using near field, which permit attenuation or delay of a magnetic field to be suppressed, the electromagnetic field generating element of the present invention generates a magnetic field in a direction parallel to the surface of a constricting section by supplying current in the conductive member, and applying a laser beam from the side of the substrate to the constricting section, and a surface plasmon is excited by an magnetic field vector vertical to the surface of the constricting section, thereby generating near field from the surface facing the interface between the substrate and the constricting section.

Electro magnetic field generating element, information recording and reproducing head and information recording and reproducing device

An aperturefor producing an evanescent wave is provided at an n-Au electrode. The apertureis directed roughly perpendicularly to a direction in which end facesof an active layerof an optical device oppose to each other, and therefore, laser light generated in the active layeris made incident in the form of the p-polarized light. By the incidence of the p-polarized laser light, an evanescent wave of a comparatively great intensity is obtained from the aperture. With this arrangement, an optical device capable of obtaining an evanescent wave of a comparatively great intensity is provided.

Optical device and optical sensor

A magnetic signal recording method of the present invention superimposes a recording edge of a recordable region on a region where there is substantial equality between (a) a coercive force in a region on a magnetic recording medium in which the coercive force has been varied, and (b) magnetic field intensity, which is generated by a magnetic recording head. The magnetic field intensity has a magnetic field distribution whose lowering rate in an in-track position is maximum in the region. The magnetic recording head, whose recording magnetic field is distributed in a rectangular shape, is used in this way so as to form a magnetic bit having a rectangular shape that is suitable for reproduction performed by a common reproduction head having a rectangular reproduction region, thereby improving an S/N of a reproduction signal dramatically.

Magnetic signal recording method and magnetic recording-reproduction apparatus

An information write/read head writes or reads information on or from recording tracks by the heat-assisted system. The information write/read head includes a magnetic head provided in such a manner that a longitudinal direction of a magnetic gap crosses a scanning direction. Further, the information write/read head includes an aperture slit having a length of not less than a diffraction limit of a light beam, and a width shorter than the diffraction limit in the direction orthogonal to the recording track, which is formed in such a manner that the longitudinal direction thereof is aligned in a scanning direction of the recording track.

Information write/read head including an optical slit having a light emitting section whose width is shorter than a light beam diffraction limit

An information recording and reproducing device includes a magnetic information detecting section for magnetically detecting magnetic information recorded at a given position on a recording medium, an optical information detecting section for optically detecting optical information recorded at a given position on each track of the recording medium, and a positional control section for controlling a position on the track using the detected magnetic information and optical information.

Information recording and reproducing device and tracking servo system therefor

A magnetic recording medium, which includes a substrate and an amorphous magnetic layer, made of an amorphous magnetic material, for magnetic recording of data, is provided with an underlayer between the substrate and the amorphous magnetic layer, the underlayer being made of amorphous metal element, and having a mean thickness of 10 nm or less. In this manner, movement of magnetic domain walls of the amorphous magnetic layer is effectively limited by minute irregularities on a surface of the underlayer. This realizes a stable formation of a minute recording mark. This realizes recording having a sufficient signal quality, even when the high-density recording is performed by forming such a minute recording mark that a shortest length of the recording mark is less than 100 nm. Moreover, this allows the magnetic recording medium to have a simplified layer structure. Further, a magnetic recording apparatus magnetically records data onto a magnetic recording medium having the above arrangement, by heating a portion of the magnetic layer by radiating a light beam locally, and by applying a magnetic field on at least part of the portion of the magnetic layer on which the light beam is radiated. This provides a magnetic recording apparatus for high-density recording.

Magnetic recording medium and magnetic recording apparatus using same

A composite magnetic head device includes a recording head and a reproducing head for magnetically recording and reproducing information on and from a recording medium, and further includes heat sources for heating the recording medium when recording and reproducing. As the heat sources, diffraction grating patterns for the recording head and the reproducing head are formed independently. With this structure, when recording and reproducing information based on the thermal distribution of the recording medium heated by the heat sources, the thermal damage on the recording medium can be suppressed, and the likelihood of such problem that the recording medium is heated too much and the information recorded in the heated portion are erased can be prevented.

Composite magnetic head device

A light emitting device for focusing a laser beam without adopting an optical lens system is provided, as well as a composite magnetic recording head and a magnetic recording device, which realize a smaller laser spot diameter and a sharp magnetic field distribution, whereby an optical-assisted high density magnetic recording can be realized, and which also realize a simplified head structure, and improvements in productivity and costs. The composite magnetic recording head is prepared by integrally forming a magnetic coil layer for use in magnetic recording at around the center of the surface-emitting laser aperture, and further, a shielding plate is formed at the center of the laser aperture. As a result, a laser beam can be focused on the irradiation surface of the magnetic recording medium at portion right below the shielding member so as to locally heat the irradiated portion, and further a magnetic field for magnetic recording is applied in the laser heated portion, thereby realizing a high density magnetic recording.

Magnetic recording head and magnetic recording device

An optical recording medium includes a recording layer and a mask layer on a substrate. The mask layer is formed of a material whose light transmittance is decreased by light irradiation and is increased by heating.

Optical recording medium and reproducing method therefor

A magnetic storage medium includes a magnetic storage medium that exhibits a magnetic compensation temperature specified higher than room temperature to minimize effects of heat generated by a head using magneto-resistance effect. In a heat assisted recording and reproduction method using such a magnetic storage medium, during reproduction, the S/N ratio in a reproduction signal is enhanced by optimizing the bias current applied to the head using magneto-resistance effect. A magnetic storage medium and a heat assisted recording and reproduction method using such a magnetic storage medium whereby information is magnetically recorded and reproduced by heating a read-out domain are offered that enables signal reproduction with a good S/N ratio despite possible use of a head exhibiting magneto-resistance effect.

Magnetic storage medium and heat assisted recording and reproduction method

A thermomagnetic recording medium includes a thermal change layer whose thermal conductivity is induced to change by a metal-to-insulator transition, is greater on a lower temperature side of a transition temperature and is smaller on a higher temperature side thereof. A thermomagnetic recording method includes setting a recording or reproducing temperature higher than the temperature of the recording medium at the circumference of a light spot and higher than a threshold temperature for change of the thermal conductivity of the thermal change layer. A thermomagnetic recording and reproducing device is provided with the above-mentioned thermomagnetic recording medium, an optical pickup and a magnetic head and conducts recording and reproduction by the above-mentioned thermomagnetic recording and reproducing device.

Thermomagnetic recording medium, thermomagnetic recording and reproducing method, and thermomagnetic recording and reproducing device

Growing community of inventors

Nabari, Japan

Kunio Kojima