Hitachi, Ltd.

Hitachi Global Storage Technologies Japan, Ltd.

Hgst Netherlands, B.v.

Norifumi Miyamoto

Yoshio Sato

Nobuyoshi Tsuboi

Hiroshi Sasaki

Satoshi Shimada

Hiroaki Koyanagi

Hideki Nihei

Akira Morinaga

Takayoshi Ohtsu

Hiroyuki Minemura

Tetsuo Ito

Atsumi Watanabe

Satoshi Shigematsu

Takao Imagawa

Koichi Nishioka

Shuichi Kojima

Kouji Kataoka

Masatoshi Arasawa

Satoshi Tabata

Masahiro Ito

Kouji Nishioka

Masahiko Ibamoto

Kazuo Shiiki

Shinji Narishige

Kanji Kawakami

Ryo Hiraga

Ryuji Watanabe

Hirotsugu Fukuoka

Chiaki Ishikawa

Masanori Tanabe

Kouichi Shimizu

Shinji Ohyama

Masahiko Hatatani

Mitsuo Suda

Eiji Nakanishi

Manabu Sato

Ito Tetsuo

Satoshai Shimada

A hard disk drive (HDD) is described which includes a magnetic field-generating device in the vicinity of a load/unload ramp such that the write head moves into a magnetic field generated by the device while the head is being unloaded from disk, whereby the magnetic field pins in a predominant direction the direction of magnetization of a magnetic shield associated with the write head, and away from the direction toward the disk. Recording magnetic field leakage associated with the shield is thereby suppressed and corresponding far track interference is inhibited.

Magnetization control for magnetic shield in magnetic recording head

In one embodiment, a magnetic head slider includes at least one magnetic head element chosen from a group consisting of: a write element adapted for writing data to a magnetic recording medium and a read element adapted for reading data from the magnetic recording medium, a heater element adapted for controlling a flying height of the at least one magnetic head element above the magnetic recording medium, a contact sensor element adapted for detecting contact between the magnetic head slider near the at least one magnetic head element and the magnetic recording medium, and shared terminals adapted for supplying voltage to the heater element and for conveying signals from the contact sensor element. Other magnetic head sliders and methods of use are described according to additional embodiments.

Magnetic head slider having shared heater and contact sensor terminal pads

A magnetoresistive head comprises a free magnetic layer that has first and second free magnetic films sandwiching a non-magnetic intermediate film therebetween, the respective magnetizing directions of the first and the second free magnetic films are antiparallel. The length of the free magnetic layer in the direction of the track width is 200 nm or less, and a difference between a product of saturation magnetic flux density and a film thickness of the first free magnetic film, and that of the second free magnetic film is within a range from 1 to 3 nmT. By this structure, the variation of output and the variation of asymmetry is greatly decreased at a track width of 200 nm or less.

CPP magneto resistive head with decreased variation in asymmetry and output

A magneto-resistive effect head including: an antiferromagnetic layer; a pinned layer which is formed on the antiferromagnetic layer and whose magnetizing direction has been fixed; a spacer formed on the pinned layer; a free layer formed on the spacer; and magnetic domain control layers having antiferromagnetic flims and magnet layers for performing a magnetic domain control of the free layer; wherein the each of the antiferromagnetjc films is formed on the free layer; wherein the each of magnet layers has at least two magnetic films coupled anti-ferromagnetically through at least one nonmagnetic film; a pair of lead layers for supplying a current to the stack of layers; and wherein seed layers are formed between the antiferromagnetic films and the lead layers.

Magnetic head with magnetic domain control structure having anti-ferromagnetic layer and plural magnetic layers

In a narrow magnetoresistive head having a magnetic domain control film comprising a single layer of magnetic film or magnetic films antiferromagnetically coupled by means of a nonmagnetic member, it has been found that the magnetic domain can be controlled with a smaller magnetization film thickness product than anticipated so far and the range is defined relative to the geometrical track width in the present invention. By defining the magnetization film thickness product of the magnetic domain control film within a prescribed range of the invention, a magnetic head having higher output than usual and having stable output with no hysteresis in the transfer curve and with no output fluctuation can be attained.

Magnetoresistive head having defined relationships between the tract width and magnetization film thickness product to permit no hysteresis in the transfer curve

Magneto resistive head and magnetic recording apparatus

The invention provides a magnetic domain controlling structure wherein a lamination stack Madjacent to a magnetoresistive stack of a GMR, CPP-GMR or TMR magnetic head has at least two magnetic filmsandanti-ferromagnetically coupled through a non-magnetic film, or the lamination stack Mdisposed on the end portions of the free layer of the magnetoresistive stack of the GMR magnetic head has a magnetic layer anti-ferromagnetically coupled to the free layerthrough the non-magnetic film. Ferromagnetic film deposition dead zone area problems and the consequent problem of film rippling in free layer portions that reduces element sensitivity are prevented, as is the problem of increased error from read drift in the magnetic field exchange coupling method, resulting in a highly stable, highly sensitive MR head with no loss of magnetic field intensity.

Magnetic head with a lamination stack to control the magnetic domain

In a magnetic disk device having a composite head with an induction type of recording head adjacent a magneto-resistance effect type of reproducing head, a read error relief is provided to relieve read errors caused by Barkhausen Noise or Base Line Shift phenomenon inherent to the magneto-resistance effect type of reproducing head. Upon occurrence of a read error, a re-try function is first executed, and a track offset function is executed for relief of the read error. However, if the read error is not relieved after the offset operation and the re-try operation have been performed a predetermined number of times, then a pseudo write-in and/or read current control operation is performed together with the offset operation and/or re-try operation for a predetermined number of times. The control operation varies the magnetic domain structure in the head magnetic film (MR film). The variation of magnetic field and/or read current in the head magnetic film causes the magnetic domain structure of the head magnetic film to be varied, so that the Barkhausen Noise or the Base Line Shift phenomenon are extinguished.

Magneto-resistance effect type of recording/reproducing head

An information recording and erasing method and apparatus of an optical memory medium including a substrate, a guard film, and an intermediate layer portion so disposed between said substrate and said guard film as to include at least a recording material layer having a phase changing with temperature and include at least one good conductor layer, comprising the steps of supplying magnetic flux varying relatively to said good conductor layer to generate eddy currents within said good conductor layer, and heating said recording material layer with heat generated in said good conductor due to the eddy current loss to effect information recording and erasing with respect to said recording material layer.

Optical memory medium and its information recording and erasing method

An optical head including a substrate, an optical waveguide formed on the substrate, a light source formed on a portion of the substrate, a collimator lens for converting light from the light source into parallel light rays, an objective lens for focusing light from the collimator lens onto a recording medium and for converting reflected light from the recording medium into parallel light rays, a beam splitter for dividing light from the objective lens into two parts to send out one of the parts in a predetermined direction, a coupling lens for focusing light from the beam splitter on a position, and a photodetector for detecting light from the coupling lens, is disclosed, in which the collimator lens, the objective lens, the beam splitter, the coupling lens and the photodetector are integrated on the substrate, and the collimator lens or an objective lens supporting part is made flexible to vary the position of the focus of the collimator lens or objective lens by piezo-electric elements.

Intergrated optical head with flexible substrate portion

An optical head is disclosed, in which a plate-shaped optical wave guide comprises an optical system including a collimator lens, a beam splitter and an objective lens; a laser light source for emitting a laser light in the form of a light beam which is to be impinged on an optical recording medium; and electro-acoustic transducers are disposed between the beam splitter and the objective lens, the transducers being adapted to be driven by the outer electrical signal for producing surface acoustic waves in the optical wave guide, thereby establishing a condensation and rarefaction distribution in refractive index in the optical wave guide which distribution influences the direction of transmission and the degree of focusing of the light beam passing therethrough so that regulation of the tracking and the focal length can be effected without any mechanical movements.

Optical head with optical beam control using acoustic wave device

A laser light flux is divided and synthesized so that its light intensity distribution is changed from a Gaussian distribution to a non-Gaussian distribution. When a laser light flux having a Gaussian distribution is irradiated onto a dividing prism, it is divided into a left part and a right part which are refracted right and left inversely from each other. When the right and left parts are incident on a synthesizing prism, they are refracted again and travel to be overlapped with each other on a recording medium. The light intensity distribution on a segment at the apex of the synthesizing prism is weaker at the central part and stronger at the peripheral part. This is because the light fluxes resulting from the division are inverted in their position so that the central part of the Gaussian distribution is separated left and right while the peripheral part with a weaker light intensity is centered.

Optical recording and reproducing device

In the present invention, a micro Fresnel lens in the shape of a thin film is used. A lens driving member constructed of piezoelectric transducers or of magnets and coils is disposed around the lens. The focus of the lens is adjusted by controlling applied voltages to the piezoelectric transducers or the coils.

Beam spot control device using a thin micro lens with an actuator

A film of a crystal - crystal phase transformation type optical recording alloy is formed on an insulating substrate. Information is erased from the alloy film by heating it with an expedient other than a laser beam. Information is read by sensing reflected light of light projected on the alloy film.

Optical information recording device

The present invention employs as a recording medium a metal or alloy which exhibits an intercrystalline transition before and after writing. In the present invention, two light beams of unequal wavelengths are used so as to write information with the light beam of the longer wavelength and to erase information with the light beam of the shorter wavelength. In changing a written content, a wavelength with which the reflection rate of the recording medium increases is used.

Optical information apparatus and method of recording and erasing

Growing community of inventors

Chigasaki, Japan

Norifumi Miyamoto