Abstract: An apparatus and method for the fiber optic sensing of an amplified signal using Stimulated Raman Scattering in a wellbore. The apparatus includes a fiber optic communication medium extending from a well head of the wellbore to a downhole environment of the wellbore, a light source, a detector, and a signal pump all being in photo-communication with the fiber optic communication medium and positionable proximate the well head, and at least one fiber optic sensing device in photo-communication with the fiber optic communication medium being positionable downhole in the wellbore. The method of using the apparatus allows for the determination of downhole parameters associated with the wellbore and includes inputting at least two optical signals having differing wavelengths into the fiber optic communication means, returning an amplified signal from a fiber optic sensing device, and detecting the amplified signal.

Abstract: An improved optical power transient control scheme is provided for optical amplifiers used in long haul, high capacity DWDM optical networks. The optical power transient control scheme employs a combination of feed-forward and feedback control mechanisms to adjust the pump laser current of an amplifier. In this way, the optical power transient control scheme allows for very fast detection of transient changes in optical input power and fast control settling time with minimal optical power degradation.

Abstract: An optical amplifier comprises: (i) an input port for providing optical signal to the amplifier; (ii) an output port for providing amplified optical signal out of the amplifier; (iii) at least two optical fibers, one optical fiber having positive dispersion DI of greater than 10 ps/nm/km in a 1550 nm to 1620 nm wavelength range, the other fiber having negative dispersion D2 of less than −5 ps/nm/km in a 1550 nm to 1620 nm wavelength range, wherein the length of each of said optical fiber is chosen to provide the amplifier with a predetermined amount of dispersion.

Abstract: A scanning microscope possesses at least one illumination source for emitting an illuminating beam that is conveyed via a beam deflection device and an optical system to a specimen and scans the latter, the beam deflection device defining at least one illuminating beam rotation point. A device for axial displacement in particular of the beam deflection device, or of a lens preceding the objective, is provided for imaging of an image of the illuminating beam rotation point into the pupil of the objective.

Abstract: An optical system with improved boresight stability having optical elements and a beam expander oriented on a chassis, wherein the beam expander is mounted for minimal movement. By minimizing movement of the beam expander, the angular error of a laser beam travelling through the optical system and subject to various angular tilt errors is reduced by an amount inversely proportional to the magnification ratio of the beam expander based on optical principles. In one embodiment the beam expander is mounted on a highly stiff location on the chassis and away from thermal stresses. Another embodiment is to mount the beam expander to a structural support of a higher assembly. The present invention isolates the beam expander from the instability of individual optical elements and from deformation of the optical bench that impairs the performance and diminishes benefits otherwise gained from the optical principles.

Abstract: Telescope with a main tube in which a crosshair plate is movably arranged in an intermediate image plane. The crosshair plate can be moved relative to the main tube by means of a vertical drive and a horizontal drive. An index plate is associated with the crosshair plate of the telescope, is tiltably mounted in the main tube, and executes a tilting movement accompanying the movement of the crosshair plate in a horizontal direction.

Abstract: A light-polarizing film is provided which possesses a light transmittance of not more than 0.3% at wavelengths of from 430 nm to 500 nm inclusive when irradiated with a linearly polarized light with a vibration plane parallel to an absorption axis of said film, and a light transmittance of not less than 77% at wavelengths of from 430 nm to 500 nm inclusive when irradiated with a linearly polarized light with a vibration plane perpendicular to the absorption axis of said film.

Abstract: A spectral interleaver providing flat top spectral transmission passbands and athermal operation is disclosed. The spectral interleaver may comprise a pentagon-shaped birefringent crystal, a polarization beam splitter, and a dielectric mirror at one facet of the crystal. Prisms and polarizing beam splitters can be employed for operation with an unpolarized input beam. The cavity formed by the mirror and the crystal serves as a spectrally dispersive mirror. Front mirror reflectivity is provided by the air-crystal (or other medium-crystal) interface. Proper mirror reflectivities can be achieved by selecting the angle &thgr; of the pentagon-shape crystal. By selecting the proper air space between the mirror and the crystal surface and the crystal length, the interleaver can have a flat top transmission function.

Abstract: An optical system includes a diffractive optical element having a diffraction grating provided, on a lens surface having curvature, in a concentric-circles shape rotationally-symmetrical with respect to an optical axis. A sign of the curvature of the lens surface having the diffraction grating provided thereon is the same as a sign of a focal length, in a design wavelength, of a system composed of, in the optical system, a surface disposed nearest to an object side to a surface disposed immediately before the lens surface having the diffraction grating provided thereon, and is different from a sign of a distance from the optical axis to a position where a center ray of an off-axial light flux enters the lens surface having the diffraction grating provided thereon. Further, an apex of an imaginary cone formed by extending a non-effective surface of the diffraction grating is located adjacent to the center of curvature of the lens surface having the diffraction grating provided thereon.

Abstract: Novel optical devices, which are referred to as composite prisms in this document, have been designed, produced and tested. They have the potential to be useful for a number of vision related applications. For high prism diopter (15 prism diopters or more), composite prisms have resulted in thinner, lighter and lower aberration optical devices than the standard ophthalmic prisms currently in use. They also offer significantly better optical quality than the Fresnel press-on prisms which are also used to correct several ophthalmic disorders.

Abstract: A light modulator includes elongated elements arranged parallel to each other. In a first diffraction mode, the light modulator operates to diffract an incident light into at least two diffraction orders. In a second diffraction mode, the light modulator operates to diffract the incident light into a single diffraction order. Each of the elongated elements comprises a blaze profile, which preferably comprises a reflective stepped profile across a width of each of the elongated elements and which produces an effective blaze at a blaze angle. Alternatively, the blaze profile comprises a reflective surface angled at the blaze angle. Each of selected ones of the elongated elements comprise a first conductive element. The elongated elements produce the first diffraction when a first electrical bias is applied between the first conductive elements and a substrate.

Abstract: A variable dispersion compensator comprising an optical incidence/output device for propagating wavelength division multiplexed light; an optical multiple reflector on which the wavelength division multiplexed light emitted from the optical incidence/output device is incident for repetitive reflections; and an optical reflection device for reflecting the wavelength division multiplexed light emitted from the optical multiple reflector toward the optical multiple reflectors the device composed of a second lens and a reflecting element and being capable of controlling the distance from the optical multiple reflector. A temperature adjusting element and a temperature detecting element are arranged via a thermal-conductive elastic member on a surface of the optical multiple reflector at a portion where no drop occurs in the intensity of the wavelength division multiplexed light incident/emitted. The temperature of the optical multiple reflector is controlled by a controller.

Abstract: An arrangement for rotatable adjustment of a cap on an eyepiece housing with a stationary pin pointing radially outward from the eyepiece housing and a groove which is assigned to the pin, arranged on the inner side of the cap and rises in the axial direction, is characterized in that, in a plane at right angles to the longitudinal axis of the eyepiece housing, three pins are arranged on the latter, the heads of which pins have at least approximately the same spacing from the longitudinal axis, and in that the sliding bottom of the groove assigned to each pin has a smaller spacing in relation thereto, so that the cap bears against the pins under prestress.

Abstract: A color wheel with a balancing groove comprises a carrier, having a central axis, a external surface, and a periphery, and rotates along the central axis; a set of filter plate sharing the same central axis with the carrier, wherein one or more annular groove is disposed on the external surface of the loading element, and a balancing substance is added into the annular groove to balance the color wheel.

Abstract: Providing a method and apparatus for efficiently irradiating a uniform laser light on an irradiation surface even when a laser light of high coherence or a large size substrate is used. The laser irradiation apparatus of the invention comprises a laser; means for dividing a laser light emitted from the laser into plural laser beams; means for synthesizing the laser beams on the irradiation surface or place in the vicinity thereof thereby forming a laser light having a periodical energy distribution; and means for moving the substrate relative to the laser light. Such a laser irradiation apparatus may be used to anneal the overall surface of a semiconductor film.

Abstract: A backlit display device (118) for the automatic viewing of lenticular image cards (62) comprising an illumination source (56) which by design selectively illuminates individual images formed onto lenticular media. The display's illumination source (56) directs light through the lenticule side of the lenticular image card (62) in conformance to the card's viewing distance (54) and selected viewing angle (72) to sequentially illuminate each image in turn.

Abstract: A projection type image display apparatus comprises a light source unit; an integrator unit for mixing luminous fluxes emitted from the light source unit so as to homogenize their light quantity distribution; a curved mirror for bending the optical path of luminous fluxes, which are turned into uniform light by the integrator unit, toward a projection unit; and the projection unit for causing the luminous fluxes to carry image information and projecting these luminous fluxes onto a screen.

Abstract: A pellicle comprising a box-shaped pellicle frame having top and bottom openings, and a pellicle sheet bonded to the pellicle frame to cover one of the openings of the pellicle frame, wherein the pellicle frame is made of quartz glass, a plurality of vent holes are formed as distributed on opposing side walls of the pellicle frame, and the size of the vent holes in the direction of the height of the pellicle frame is at most ⅗ of the height of the pellicle frame.

Abstract: Fine-tuning of the optical path length in etalon cavities is achieved by slight variations of the cavity's index of refraction. Such index of refraction variations are accomplished by varying the relative gas mixture in gas-gap etalons or UV-exposing doped glass layer(s) in solid etalons or gas-gap+glass etalons.

Abstract: A zoom lens device includes a zoom optical system, in which front, middle and rear lens groups are set at one focal length between a wide-angle end where a focal length is short and a telephoto end where the focal length is long. Lens barrels move in first and second regions to move the front, middle and rear lens groups along an optical axis. The lens barrels, when in the first region, focus the zoom optical system with a predetermined focal length kept by maintaining an interval between the front and middle lens groups, and when in the second region, change the focal length of the zoom optical system. A combination of a cam follower pin and a cam groove effects focusing by moving the middle lens group relative to the front lens group along the optical axis when the lens barrels are in the second region.

Abstract: An optical pickup apparatus having an objective lens which is formed of a single lens such that the maximum slope angle of a surface of the lens is less than 55° with respect to a high NA of 0.7 or more. The objective lens can be manufactured to satisfy a condition of allowance in optical aberration and have a high NA of 0.7 or more unlike a typical objective lens formed of a single lens. Also, the optical pickup apparatus adopting the objective lens can be used for high density recording and reproduction and provide a reduced volume, a simple structure, and/or a low price. Also, since the optical pickup apparatus adopting the objective lens has a very short working distance, the first reflection surface recording method can be adopted. Accordingly, the thickness of the optical pickup apparatus can be manufactured as thin as a protective layer of a typical recording medium.

Abstract: An objective lens (1) for an optical disk, which focuses a light beam from a light source, is designed so that a third-order coma aberration generated when the objective lens is inclined at a unit angle is larger than a third-order coma aberration generated when the optical disk (2) is inclined at the unit angle, mounted on an actuator for inclining the objective lens according to an inclination amount of the optical disk, and used. With this structure, it is possible to obtain an objective lens for an optical disk that has a large numerical aperture and is easy to manufacture and assemble, and in which the third-order coma aberration generated when the optical disk surface is inclined owing to a warp or the like can be corrected by small inclination of the objective lens, so as to reduce a residual astigmatism, which is generated according to the inclination amount, after the correction.

Abstract: An optical wavelength demultiplexer includes an optical lens, a first-side waveguide and a plurality of second-side waveguide. The lens has a wave number distribution-surface having a section where an angular frequency is constant, and said section having a shape which generally represents at least a part of an ellipse or a circle; a medium allowing group-velocity directions toward an inside of the section to allow said medium to exhibit a lens effect; a finite thickness defined by a distance between two parallel planarized surfaces of the medium; a first focusing point at an inside position of the lens; and a second focusing point at an outside position of the lens. The first-side waveguide is positioned for incidence of a wavelength-multiplexed optical signal into the lens. The plurality of second-side waveguide is so aligned that terminals thereof are positioned at respective focusing points of respectively different-wavelength components included in the wavelength-multiplexed optical signal.

Abstract: A lens barrel in accordance with the present invention includes a stationary frame and a second group-of-lenses holding frame. One end of a second group-of-lenses main rod is attached to the second group-of-lenses holding frame with a sleeve between them so that the second group-of-lenses main rod can freely slide. Furthermore, one end of the second group-of-lenses sub rod is fixed to the second group-of-lenses holding frame. Consequently, the other ends of the second group-of-lenses main rod and second group-of-lenses sub rod are attached to the stationary frame so that the second group-of-lenses main rod and second group-of-lenses sub rod can freely slide. Consequently, the second group-of-lenses holding frame is borne while being permitted to freely advance or withdraw relative to the stationary frame without rotating by the main rod and second group-of-lenses sub rod. The main rod is fixed to neither the stationary frame nor lens holding frame but can slide by itself.

Abstract: An apparatus for mounting optical components and adjusting its orientation with respect to the optical axis of other components in an optical system. In one embodiment, the multi-axis gimbal mounting apparatus utilizes a single piece main structure having a pair of live hinges and a locking feature that enhances two kinds of stability. First, the adjustable elements of the mount remain in the intended position when the locking mechanism is actuated with minimal cross-talk between the locking features and the adjustment features. Second, the adjustable elements of the mount remain in the intended position when the mount or the system in which it resides is exposed to extreme environmental perturbations of vibration, temperature, shock, and acceleration. This mount is suitable for use in military laser systems, cryogenic systems, and other industrial optical instruments subjected to harsh environments such as aircraft, ship, and battlefield deployed devices.

Abstract: A binocular of this invention includes a pair of objective optical systems, a pair of eyepiece units for integrally holding erecting optical systems and eyepiece optical systems, and a holding member having a first holding portion for holding one of the pair of eyepiece units and a second holding portion for holding the other one of the pair of eyepiece units. The holding member is deformed such that the pair of eyepiece units has a predetermined positional relationship.

Abstract: An optical film for use in transparent displays, such as reflective LCDs. The optical film has three-dimensional, prismatic structures that reflect incoming light. The prismatic structures are elongate structures configured so that the reflecting facets orient the reflected light in desired reflective light pattern. The pattern shape and intensity can be controlled by the shape and dimensions of the various reflecting facets. In one embodiment, the height of the prismatic structure varies along the elongate structure.

Abstract: The present invention discloses an image-forming optical system provided with a plurality of curved mirrors whereby two points at different distances are made to have an optically conjugate relationship, sequentially starting with a first conjugate point which is nearer when an optical path is traced from the first conjugate point to a second conjugate point which is farther, comprises, a first mirror which reflects luminous flux from the first conjugate point to transform the luminous flux into substantially parallel luminous flux, and a second mirror which reflects the luminous flux reflected by the first mirror while keeping the luminous flux substantially parallel.

Abstract: If a computer disk drive is stolen and later recovered, there is no way currently to know if the disk was accessed. The present invention offers a solution to the problem of detecting disk access and provides means for implementing quota and usage restrictions as well as detection schemes. The present invention teaches to use a one-way counter which counts the number of bytes written to and read from the drive. The counter itself can only be read. Operating system software can make use of the counter to provide access control and access detection.

Abstract: The invention discloses an assembly comprising an adjustable heat flux mechanism suitable for thermally assisted information processing and control. In one embodiment, the assembly discloses a directed energy source for heating a media, a temperature sensing element for measuring/inferring the temperature of the media, and a controller for mutually positioning the energy output by the directed energy source and the media for thereby controlling the power directed to the media in accordance with the temperature sensing element.

Abstract: A method for forming a magnetic pattern by applying a first external magnetic field to a magnetic recording medium having a magnetic layer to magnetize uniformly the magnetic layer in a predetermined direction and heating locally the magnetic layer while a second external magnetic field is applied thereto, whereby the heated portion is magnetized in the direction opposite to the predetermined direction, wherein the second external magnetic field has a pulse-like magnetic field component.

Abstract: A signal processing circuit for a magnetic recording/reproducing apparatus, including at least an AGC, a PLL, a LPF, an equalizer circuit and a detection circuit, wherein a coefficient compensation circuit is formed by defining a constitution of the equalizer circuit, an error detection circuit is provided which operates by receiving input from the detection circuit, and the LSI is formed by a plurality of analog and digital chips, and the analog and digital chips are connected by current-output type D/A converters connected to at least the AGC and the PLL.

Abstract: A system and method for controlling the position of a digital data storage device slider through the use of an electro-thermal micromechanical actuator is disclosed. A movable member is etched into a face of a slider opposite the air-bearing surface of the slider. The movable member is substantially freestanding in relation to the slider, having only a single end connected to the slider. An electrically actuated heater element with two parallel current paths is disposed on the movable member. One of the current paths is substantially narrower than the other current path. When a current is passed through the heater element, the narrower current path heats up more quickly than the wider current path. By varying the current passed through the heater element in a selected manner, a distortion of the movable member is harnessed and used to create a relative motion in the slider body, allowing the slider to be quickly and exactly located over the centerline of a track of a storage device.

Abstract: A method of positioning a selected recording channel on a recording head relative to an optical servo system includes positioning the optical servo system at a first position relative to the selected recording, processing an alignment tape to determine a lateral offset between the optical servo system and the selected recording channel and positioning the optical servo system at a second position relative to the selected recording channel using the lateral offset. An alignment tape is also provided, which includes an elongated continuous web of flexible plastic substrate material having two edges and defining a front major surface and a back major surface, a magnetic storage medium formed on the front major surface, an inert medium formed on the back major surface and a track of alignment voids for indicating actual lateral displacement of the selected recording channel relative to the optical servo system.

Abstract: A disk for a disk drive data storage device contains embedded track identifying fields which identify a track within a range of tracks, the range being less than the full range of tracks on the disk surface. The full identity of a track during a track seek operation is determined by iteratively assuming a track identity and estimating acceleration of the transducer based on the assumed track identity, until a track identity is found for which estimated acceleration meets some pre-determined threshold. Preferably, embedded servo fields are recorded at angularly spaced intervals on the disk surface, and every Nth servo field contains a Gray code full track identifier, while all servo fields in between contain abbreviated Gray code fields which identify a track within a range of tracks.

Abstract: The hard disk drive comprises: a magnetic disk 2 having servo information stored; magnetic heads 4 seeking on the magnetic disk 2 and staying at a predetermined position to read or write data; a voice coil motor 6 moving the magnetic heads 4 to the predetermined position of the magnetic disk 2; a position controller supplying a driving current to the voice coil motor 6 based on the servo information read by the magnetic heads 4. The position controller includes: a CPU 12 outputting a speed control value based on the servo information; a DAC 7 and a VCM driver 8 converting the speed control value into the driving current; and a controller 10 limiting a driving speed of the voice coil motor 6 in a case that an output timing of the speed control value is shifted.

Abstract: An apparatus and method optimizing a model reference generator of a servo circuit to substantially mimic actual read/write head positions are disclosed. The servo circuit includes a microprocessor with associated random access memory storing a current profile and a set of optimized filter coefficients. The coefficients optimize a delay length of a finite impulse response filter, which delays passage of the current profile to a double integrator embedded in the microprocessor. The double integrator generates the substantially mimicked head positions.

Abstract: The present invention is to provide a magnetic tape recording/reproducing device capable of accurately positioning a magnetic tape relative to a magnetic head to thereby improve recording/reproduction characteristics to or from the magnetic tape even when the running direction of the magnetic tape is inverted between forward and reverse directions. First guide rollers are provided so as to swing between a first inclined position and a second inclined position along a tangential direction of the magnetic tape partially wound on roller portions and, where the first inclined position is such that allowing upper flanges to reside on an upstream side of the lower flanges in the tape running direction, and the second inclined position is such that allowing the upper flanges to reside on a downstream side of the lower flanges in the tape running direction. The first guide rollers are respectively provided with drive means for allowing the first guide rollers to swing between the first and second inclined positions.

Abstract: A cassette table which is moved in a cassette traveling path has a support plate which is configured by a metal plate having elasticity, side walls, and cassette pressers. A magnetic tape device has swing levers which press down projections disposed on the side walls to lower the cassette table, and seats on which the tape cassette placed on the support plate is to sit. Swinging operation of the swing levers in a stage after the tape cassette sits on the seats is allowed by flexural deformation of the support plate.

Abstract: A base of an arm having a driving projection at its tip is rotatably supported on a turn table. The turn table is provided with a first guide part and a second guide part, an outer edge part of the base of the arm and a first guide part are in contact with each other at a contact point, and a projection and a second guide part are in contact with each other at a contact point. While the arm rotates in a counterclockwise direction, the contact points are moved, and it is possible to prevent the center of the driving projection from largely deviating from a reference normal. Thus, even if a hub in which the position of the driving hole is shifted is mounted, the hub is not largely shifted in a rotation direction relative to a turn table.

Abstract: The present invention disclosed the new kind of multi layer suspension and the method for making this. The mutli-layer suspension of the present invention is comprised of a rectangular base plate section, a load beam and a flexure, said load beam can be further divided into a bending area adjacent to the base plate and a rigid area contiguous to said bending section, said suspension assembly is made up of three layers, wherein an adhesive layer is sandwiched between two stainless steel layers with parts of one of said stainless steel layers being etched off. The method for making such suspension including the steps of making three layer raw material, etching off parts of the stainless steel, etching off parts of the polyimide, and the forming and de-tab. The structure of multi-layer suspension of the present invention overcomes the problems of etching variations and misalignment exist in the traditional production of the suspension.

Abstract: A single latch that can secure an actuator arm when a hard disk drive has a clockwise rotational acceleration, or a counterclockwise rotational acceleration. The latch has a first end that can engage a first latch portion of the actuator arm when the disk drive has a clockwise rotational acceleration. The same latch also has a second end that can engage a second latch portion of the actuator arm when the disk drive has a counterclockwise rotational acceleration.

Abstract: A disk device includes a head part, an actuator part for moving the head part to an objective position, and a control part for controlling the actuator part, wherein the control part makes the actuator part shift to a reverse direction of the movement direction of the head part before a settling action of the head part starts being implemented.

Abstract: A two bump magnetic head for writing and reading information to a tape includes a merged-pole read/write element structure with inverted write elements. Each inverted write element includes top and bottom write poles. The write poles are fabricated such that the longitudinal dimension of the bottom write pole is smaller than the longitudinal dimension of the top write pole in a zero throat region. This results in an “inverted” structure. An upper portion of the bottom write pole is milled in at least the zero throat region early in fabrication to produce a precise width adjoining a write gap. The trimmed upper portion of bottom write pole results in an improved write geometry that produces tightly defined tracks.

Abstract: A magnetoresistive sensor for use in a data storage device has a recessed sensing element (magnetic tunnel junction, CPP spin valve, etc.) with an exchange biased sensing ferromagnetic (free) layer, and a flux guide that magnetically connects the sensing element to a sensing surface of the sensor. The free layer is selectively exchange biased by a layer of exchange bias material placed under non-active regions of the free layer that lie outside the sensing element and flux guide track widths. The flux guide is provided by extending the free layer from a forward edge of the sensing element to the sensor surface. Advantageously, the sensing element and the flux guide have equal track width so that magnetic flux directed from the flux guide into the sensing element is not diluted with consequent loss of sensitivity.

Abstract: Spin valve heads with overlaid leads have several advantages over butted contiguous junction designs, including larger signal output and better head stability. However, in any overlaid design there is always present at least one high resistance layer between the GMR layer and the conductive leads. This leads to an effective read width that is greater than the actual physical width. This problem has been overcome by inserting a highly conductive channeling layer between the GMR stack and the conducting lead laminate. This arrangement ensures that, at the intersection between the leads and the GMR stack, virtually all the current moves out of the free layer into the leads thereby providing an effective read width for the device that is very close to the physical read width defined by the spacing between the two leads. A process for manufacturing the device is also described.

Abstract: A magnetoresistive head including a first magnetic shield, a first electrode terminal provided on the first magnetic shield and having a first width, and a magnetoresistive film provided on the first electrode terminal and having a second width less than or equal to the first width. The magnetoresistive head further includes a second electrode terminal provided on the magnetoresistive film and having a third width less than or equal to the second width, and a second magnetic shield provided on the second electrode terminal. Preferably, the magnetoresistive head further includes a plug electrode for connecting the second electrode terminal to the second magnetic shield, and a plug side wall protective insulating film for covering a side wall of the plug electrode.

Abstract: The invention provides a magnetic head capable of positively preventing electrostatic breakdown of an MR magnetic head device, and a method of manufacturing the magnetic head. A circuit board comprises at least a pair of leads for constructing a circuit, lands connected respectively to the leads, and solder bumps formed respectively on the lands. The solder bumps are arranged in an adjacent relationship and, when the solder bumps are crushed, peripheral portions of the solder bumps are pressed or spread so as to overlap with each other. The magnetic head includes the circuit board.

Abstract: A magnetoresistance sensor structure is formed of a magnetoresistance sensor having a transverse biasing stack including a transverse pinning layer made of a transverse-pinning-layer antiferromagnetic material, and a transverse pinned layer structure overlying the transverse pinning layer, a spacer layer overlying the transverse pinned layer structure, a sensing stack overlying the spacer layer, and a decoupling layer overlying the sensing stack. A longitudinal biasing stack overlies the magnetoresistance sensor and includes a longitudinal pinned layer, and a longitudinal pinning layer overlying the longitudinal pinned layer and made of a longitudinal-pinning-layer antiferromagnetic material. The transverse-pinning-layer antiferromagnetic material and the longitudinal-pinning-layer antiferromagnetic material are preferably Pt—Mn or Ni—Mn.

Abstract: A magnetic head using magneto-resistive effect includes a spin-valve type giantmagneto-resistive effect element or tunnel-typemagneto-resistive effect element type lamination layer structure portion in which a free layer 4 made of a soft magnetic material of which the magnetization is rotated in response to an external magnetic field, a fixed layer 6 made of a ferromagnetic material, an antiferromagnetic layer 7 for fixing the magnetization of this fixed layer 6 and a spacer layer 5, i.e., nonmagnetic conductive layer or a tunnel barrier layer are laminated with each other.