Abstract: Provided are a patterned magnetic recording medium which has an extremely planarized surface and a method of manufacturing the same. The medium includes a patterned magnetic layer including a plurality of magnetic columns that are arranged with a predetermined pitch therebetween; a substrate that supports the patterned magnetic layer; and a boundary layer, which is filled in gaps between the magnetic columns of the patterned magnetic layer. Thus, an air bearing due to stable airflow is created over the magnetic layer, and magnetic recording/reproduction are easily achieved at ultrahigh density.

Abstract: A method of fabricating a diffusion barrier using a gas cluster ion beam apparatus is disclosed. The method includes generating a metal-organic gas that includes a metal-organic compound that includes an element of cobalt (Co) or cobalt and iron (CoFe). The metal-organic gas is combined with a carrier gas that is supplied to the gas cluster ion beam apparatus (GCIB). The GCIB processes the carrier gas to form a beam of gas cluster ions that include the metal-organic compound. The beam irradiates an interface surface of a target material (e.g. an IrMn, PtMn, or MnFe antiferromagnetic layer) and at least a portion of the Co or CoFe remains in contact with the interface surface to form a barrier that prevents a diffusion of manganese (Mn).

Abstract: A thin soft magnetic film combines a high magnetization with an insulating character. The film is formed by nitriding Fe-rich ferromagnetic nanograins immersed in an amorphous substrate. A selective oxidation of the amorphous substrate is then performed. The result is a thin, insulating, soft magnetic film of high magnetization. Many types of integrated circuits can be made which include a component using a membrane incorporating the above-mentioned thin film.

Abstract: A discrete track medium and a bit patterned medium with a high SNR are manufactured at low cost. A seed layer and a recoding layer are formed on a bottom surface and a side wall of a groove portion, which is formed between non-magnetic projected structures artificially patterned. Then, the recording layer on the projected portion is removed.

Abstract: A method of manufacturing a magnetic recording medium that exhibits high performance and high reliability includes forming a liquid lubricant layer capable of high coverage while retaining a film thickness of 1 nm to 2 nm. The magnetic recording medium includes an underlayer, a magnetic layer, a protective layer, and a liquid lubricant layer sequentially laminated or formed on a substrate. The liquid lubricant layer is formed by coating a liquid lubricant diluted with a solvent on the protective layer to a thickness of at least the surface roughness to form a thick film liquid lubricant layer, pressing a slide member against the surface of the liquid lubricant layer while rotating the medium to adhere the liquid lubricant onto the protective layer, and reducing the thickness of the liquid lubricant layer with a solvent that can dissolve the liquid lubricant to the medium surface.

Abstract: A process for producing a perpendicular magnetic recording medium comprises forming metallic nuclei or a seed layer on a non-magnetic substrate, and forming a soft magnetic under layer on the metallic nuclei or the seed layer by means of electroless plating. The soft magnetic under layer is formed while an external parallel magnetic field is applied to the non-magnetic substrate, and the substrate is rotated such that the substrate is maintained parallel to the parallel magnetic field.

Abstract: A thin-film magnetic head has a laminated construction comprising a main pole layer having a magnetic pole tip on a side of the medium-opposing surface opposing a recording medium, a write shield layer opposing the magnetic pole tip forming a recording gap layer, on the side of the medium-opposing surface, and a thin-film coil wound around at least a portion of the write shield layer. The thin-film magnetic head has an upper yoke pole layer having a larger size than the portion of the main pole layer which is more distant from the medium-opposing surface than the recording gap layer, wherein the upper yoke pole layer is joined to the side of the main pole layer which is near the thin-film coil.

Abstract: Techniques for attaining high performance magnetic memory devices are provided. In one aspect, a magnetic memory device comprising one or more free magnetic layers is provided. The one or more free magnetic layers comprise a low magnetization material adapted to have a saturation magnetization of less than or equal to about 600 electromagnetic units per cubic centimeter. The device may be configured such that a ratio of mean switching field associated with an array of non-interacting magnetic memory devices and a standard deviation of the switching field is greater than or equal to about 20. The magnetic memory device may comprise a magnetic random access memory (MRAM) device. A method of producing a magnetic memory device is also provided.

Abstract: An apparatus for manufacturing a magnetic recording disk includes a magnetic-film deposition chamber in which a magnetic film for a recording layer is deposited on a substrate; a lubricant-layer preparation chamber in which a lubricant layer is prepared on the substrate in vacuum; and a cleaning chamber in which the substrate is cleaned in vacuum after the magnetic-film deposition in the magnetic-film chamber and before the lubricant-layer preparation in the lubricant-layer chamber. The apparatus may further include a transfer system that transfers the substrate from the cleaning chamber to the lubricant-layer preparation chamber without exposing the substrate to the atmosphere.

Abstract: Improved resin-bonded powdered metal components are protected against corrosion and reduction of crush strength during contact with corrosive fluids such as alcohols, ethanol-containing fuels, glycols and peroxide-containing fuels by a resin system coating that, when cured, provides a relatively high crosslink density and relatively few hydrolysable radicals. Magnetic properties of resin-bonded powdered metal magnets are protected from heat degradation by the cured resin coating. The coating can be a heat-cured resin system comprising a phenol novolac resin and a compatible hardener. In one embodiment magnetizable powdered materials have an uncured resin system coating to provide a B-stage material that can be cured after compression shaping.

Abstract: A substrate for perpendicular magnetic recording medium 2 is provided with a soft magnetic substrate coat 5. On this soft magnetic substrate coat 5, an anticorrosion coat 5 is formed. The anticorrosion coat 6 is preferably formed so as to completely cover the entire soft magnetic substrate coat 5.

Abstract: A method and apparatus is provided for creating soft magnetic materials for low-loss inductive devices that achieves low eddy currents, low coercivity, and high permeability at high frequency. The soft magnetic material utilizes magnetic nanoparticles that take advantage of desired properties of two or more particle types. The magnetic nanoparticles are single domain particles that are optimized to enhance exchange coupling.

Abstract: The present invention provides a method for producing a magnetic recording medium having servo areas and data areas using a mold structure having a plurality of convex portions, the method, including: forming an imprint resist layer on a surface of a substrate for the magnetic recording medium, forming a convexo-concave resist pattern in the formed imprint resist layer by pressing the plurality of convex portions of the mold structure against the imprint resist layer, and transferring magnetism to the servo areas in the magnetic recording medium by applying a magnetic field to the servo areas via the mold structure.

Abstract: A system and method for measuring and neutralizing the electrical charge at the interface of a magnetic head and a magnetic storage medium, such as a disk, is disclosed. A surface treatment material is applied to the magnetic head. The surface treatment material matches the medium surface material on the surface of the magnetic storage medium. The surface treatment material on the magnetic read/write head may be a fluorinated carbon, such as a Fomblin Z-derivative, perfluoro alkyl trichlorosilane, a FC-722, or a fluorinated polymer. The surface treatment material can be applied to the magnetic head by a vapor deposition process or by a liquid immersion process. The charge on the head-disk interface can be measured by applying varying external charges to the head while reading a signal previously written to the disk.

Abstract: There is provided a tunneling magnetic sensing element having an insulating barrier layer composed of Ti—O, a high rate of resistance change (?R/R) compared with the known art, and an interlayer coupling magnetic field Hin lower than that in the known art while low RA is maintained and the coercivity of a free magnetic layer is maintained at a low level comparable to the known art; and a method for producing the tunneling magnetic sensing element. An insulating barrier layer is composed of Ti—O. A free magnetic layer is formed on the insulating barrier layer and has a laminated structure of an enhancing sublayer composed of a CoFe alloy, a Pt sublayer, and a soft magnetic sublayer composed of a NiFe alloy, stacked in that order from the bottom.

Abstract: An underlying layer is composed of Co—Fe—B that is an amorphous magnetic material. Thus, the upper surface of the underlying layer can be taken as a lower shield layer-side reference position for obtaining a gap length (GL) between upper and lower shields, resulting in a narrower gap than before. In addition, since the underlying layer has an amorphous structure, the underlying layer does not adversely affect the crystalline orientation of individual layers to be formed thereon, and the surface of the underlying layer has good planarizability. Accordingly, PW50 (half-amplitude pulse width) and SN ratio can be improved more than before without causing a decrease in rate of change in resistance (? R/R) or the like, thereby achieving a structure suitable for increasing recording density.

Abstract: A thin-film magnetic head structure has a configuration adapted to manufacture a thin-film magnetic head configured such that a main magnetic pole layer including a magnetic pole end part on a side of a medium-opposing surface opposing a recording medium, a write shield layer opposing the magnetic pole end part so as to form a recording gap layer on the medium-opposing surface side, and a thin-film coil wound about the write shield layer or main magnetic pole layer are laminated. The main magnetic pole layer includes a base magnetic pole part comprising the magnetic pole end part and a base depression distanced farther from the medium-opposing surface than the magnetic pole end part, and an embedded magnetic pole part buried in the base depression and joined to the base magnetic pole part.

Abstract: A patterned perpendicular magnetic recording medium of the type that has spaced-apart pillars with magnetic material on their ends and with trenches between the pillars that are nonmagnetic regions is made with a method that allows use of a pre-etched substrate. A nonmagnetic capping layer is located in the trenches above the nonmagnetic regions. The substrate has diffusion material in the trenches that when heated will diffuse into the magnetic recording layer material and chemically react with it. The pillars are formed of material that will not diffuse into the recording layer. The recording layer is formed over the entire substrate and a nonmagnetic capping layer that is not chemically reactive with the diffusion material is formed over the recording layer in the trenches. The substrate is annealed to cause the recording layer material in the trenches and the material in the substrate to diffuse into one another and chemically react to render the trenches nonmagnetic.

Abstract: Devices based on spinodally decomposed periodic structures and their fabrication techniques.

Abstract: A rare-earth magnet includes a magnet body made of an R—Fe—B based rare-earth magnet material (where R is at least one rare-earth element) and a metal film that has been deposited on the surface of the magnet body. The magnet further includes a plurality of reaction layers between the magnet body and the metal film. The reaction layers include: a first reaction layer, which contacts with at least some of R2Fe14B type crystals, included in the magnet body, to have received the rare-earth element that has been included in the R2Fe14B type crystals; and a second reaction layer, which is located between the first reaction layer and the metal film and which has a lower rare-earth element concentration than that of the first reaction layer.

Abstract: Disclosed is a perpendicular magnetic recording medium comprising: (a) a non-magnetic substrate including a surface with a stack of thin-film layers formed thereon; and (b) a tilted perpendicular magnetic recording layer on the surface of an outermost layer of said layer stack, wherein the easy axis of magnetization of magnetic particles of said recording layer is tilted in a radial direction at a preselected, controllable angle up to about 45° from vertical. Also disclosed are a method and apparatus for forming perpendicular magnetic recording media with controllably tilted perpendicular magnetic recording layers.

Abstract: Magnetic medium recording performance can be enhanced by irradiating a magnetic medium with ions having an acceleration voltage of between 10 keV and 100 keV to induce exchange coupling between grains of the magnetic medium. The magnetic medium is exposed to a cumulative ion dosage of between 1013 ions/cm2 and 1017 ions/cm2 using a non-patterned exposure of the magnetic medium. The ions can be selected from the group consisting of H+, He+, Ne+, Ar+, Kr+, and Xe+. Alternatively, the ions can be selected from the group consisting of Ga+, Hg+, and In+.

Abstract: A method for manufacturing a magneto-optical recording medium in which reading of recorded information is performed through domain wall displacement in a reproduction layer is provided, in which magnetic separation of groove side-wall portions is performed more reliably; as a result a magneto-optical recording medium with satisfactory recording and reproduction characteristics can be provided.

Abstract: A method for manufacturing a magneto-optical recording medium in which reading of recorded information is performed through domain wall displacement in a reproduction layer is provided, in which magnetic separation of groove side-wall portions is performed more reliably; as a result a magneto-optical recording medium with satisfactory recording and reproduction characteristics can be provided.

Abstract: A label marks a composite material. In one embodiment, the label may be printed with magnetically doped ink and may be embedded between layers of the composite during manufacture. In one embodiment, the label may be embedded on the surface of the composite material using a heat curable resin. In one embodiment, the label carries indicia that may be read with magnetic ink character recognition (MICR) or other magnetic scanning technology. In one embodiment, there is no need for visual contrast between the composite, label and/or indicia.

Abstract: Provided is a method and system for manufacturing a hard drive platen. The method includes depositing two or more types of film around a central core to form a plurality of film layers, each film layer being of a different type than its adjacent layers. Next, the deposited film layers are sectioned to expose a patterned surface. The patterned surface is then planarized and selectively etched to expose patterns comprised of one of the types of film to a predetermined depth to produce a selectively etched surface. Magnetic material it deposited within etches of the surface and the surface is then planarized to form separated magnetic tracks therein.

Abstract: A method of manufacturing a magnetic recording media includes a magnetic recording layer of a granular magnetic layer that has ferromagnetic crystal grains and an oxide nonmagnetic grain boundary or a nitride nonmagnetic grain boundary surrounding the ferromagnetic crystal grains. It further has an overcoating layer on the granular magnetic recording layer. The overcoating layer contains a nonmagnetic metal or a nonmagnetic alloy that can be diffused into the nonmagnetic grain boundary. The atoms coated on the granular magnetic recording layer diffuse into the nonmagnetic grain boundary even without being annealed, and promote to isolate the ferromagnetic crystal grains from each other. The overcoating can be removed after its formation to reduce the magnetic gap between the magnetic recording layer and the magnetic recording head.

Abstract: The invention is directed to a magnetic thick film composition comprising particles of permanent magnetic materials dispersed in organic medium wherein the medium comprises a polymer selected from polyurethane, phenoxy and mixtures thereof, and organic solvent.

Abstract: A noncontact power-transmission coil is provided. The noncontact power-transmission coil includes a planar coil and a magnetic layer. The planar coil is formed by winding a linear conductor in a spiral shape substantially in a single plane. The magnetic layer is formed by applying a liquid-form magnetic solution in which magnetic particles are mixed with a binder solvent, so as to cover one planar portion of the planar coil and a side-face portion of the planar coil.

Abstract: A magnetic sensor comprises magnetoresistive elements and permanent magnet films, which are combined together to form GMR elements formed on a quartz substrate having a square shape, wherein the permanent magnet films are paired and connected to both ends of the magnetoresistive elements, so that an X-axis magnetic sensor and a Y-axis magnetic sensor are realized by adequately arranging the GMR elements relative to the four sides of the quartz substrate. Herein, the magnetization direction of the pinned layer of the magnetoresistive element forms a prescribed angle of 45° relative to the longitudinal direction of the magnetoresistive element or relative to the magnetization direction of the permanent magnet film. Thus, it is possible to reliably suppress offset variations of bridge connections of the GMR elements even when an intense magnetic field is applied; and it is therefore possible to noticeably improve the resistant characteristics to an intense magnetic field.

Abstract: An information storage device includes a magnetic layer and a supply unit. The magnetic layer includes a plurality of regions, a first region having a first magnetic anisotropic energy and a second region having a second magnetic anisotropic energy. The first and second regions are arranged alternately, and the second region is doped with impurity ions. The second magnetic anisotropic energy is less than the first magnetic anisotropic energy. The supply unit applies energy to the magnetic layer for moving magnetic domain walls within the magnetic layer.

Abstract: An information storage device includes a writing magnetic layer including a magnetic domain wall. An information storing magnetic layer is connected to the writing magnetic layer, and includes at least one magnetic domain wall. The information storage device also includes a reader for reading data recorded in the information storing magnetic layer. The connection layer includes a first portion with a first width adjacent to the writing magnetic layer and a second portion with a second width adjacent to the at least one information storing magnetic layer. The first width is less than the second width.

Abstract: A method of producing a wall covering comprising the steps of (a) rendering a wallpaper substrate magnetically receptive by coating a wallpaper substrate with a composition comprising magnetically receptive iron oxide pigments and over-printing the wallpaper substrate. A wall covering with a magnetically receptive coating and a kit comprising such wall covering in combination with a magnet are further described.

Abstract: A nonmagnetic material-noncontact layer forming a fixed magnetic layer is formed using CoFe, a nonmagnetic material-contact layer is formed using Co, and an NOL (Nano-Oxide Layer) is provided between the nonmagnetic material-noncontact layer and the nonmagnetic material-contact layer. In addition, the average film thickness of the nonmagnetic material-contact layer is set in the range of 16 to 19 ?. Accordingly, compared to a three-layered structure composed of CoFe, an NOL, and CoFe or a three-layered structure composed of Co, an NOL, and Co, which has been conventionally used, the rate (?R/R) of change in resistance and the unidirectional exchange bias magnetic field (Hex*) can both be improved.

Abstract: For forming an annular magnetostrictive coat on an outer peripheral surface of a rotational shaft associated with a magnetostrictive torque sensor, a magnetostrictive coat forming method comprises a step of fitting a cylindrical masking jig over the outer peripheral surface of the rotational shaft and securing the masking jig to the outer peripheral surface, a step of placing the rotational shaft in a plating tank to thereby form the magnetostrictive coat by plating on the outer peripheral surface, and a step of detaching the masking jig from the rotational shaft.

Abstract: A method of manufacturing flexible magnetic tape having a permanently structured magnetic characteristic which varies from place to place in two different directions in the plane of the tape, includes:—a) coating a flexible substrate with a slurry having anisotropic magnetic particles; b) moving the substrate and slurry coating relative to a first magnetic field having a field strength which varies with time in a first direction, thereby selectively orienting the particles in areas spaced apart in a first direction; c) subsequently moving the substrate and slurry coating relative to a second magnetic field having a field strength which varies with time in a second direction making an oblique angle with the first direction, such that the magnetic particles are selectively oriented in spaced areas in both the first and further directions, and d) solidifying the slurry to fix the particles in place.

Abstract: A method of making a magnetic head comprises depositing first and second lead layers in first and second end regions which surround a central region; and forming a read sensor in the central region such that a first edge of the read sensor is disposed above an upper edge of the first lead layer and a second edge of the read sensor is disposed above an upper edge of the second lead layer.

Abstract: Wirings 2B1 are formed by application of heat treatment after an ink jet system is used to discharge a conductive liquid L onto a provisional substrate 5 having a predetermined repellent property, bonding an insulating layer 4B1 to the wirings 2B1 with an adhesive material 3B1 therebetween, peeling and removing the provisional substrate 5, and bonding and fixing the wirings 2B1 together with the insulating film 4B1 to a main substrate 1 by an adhesive material 3B1.

Abstract: A magneto-optical recording medium has a recording layer and a reflective layer on a substrate. The recording layer has a layered structure in which at least one spinel ferrite (or rutile-type oxide or hematite) layer and at least one garnet ferrite layer are piled together. It is preferable that the layered structure is formed on tracks where data are recorded. A manufacturing method comprises the steps of heat treatment in the range of 500-700° C., preferably 600-630° C., after the formation of the recording layer. In the magneto-optical recording and playback device to record and play back data, the wavelength of light for recording data is different from that for reading data, which is preferable for a magneto-optical recording medium comprising a garnet ferrite layer.

Abstract: A substrate for a perpendicular magnetic recording medium has a soft magnetic underlayer that functions as a soft magnetic backing layer of a perpendicular magnetic recording medium. The substrate for a perpendicular magnetic recording medium has a nonmagnetic base made of Al—Mg alloy or the like. The soft magnetic underlayer is formed of a Ni—P alloy containing phosphorus in a range of 0.5 wt % to 6 wt % formed by electroless plating on the nonmagnetic base. The substrate can also include a nonmagnetic underlayer formed by electroless plating on the base before electroless plating the soft magnetic underlayer. To form the perpendicular magnetic recording medium, the surface of the soft magnetic is textured using free abrasive grains. Thereafter, a nonmagnetic seed layer, a magnetic recording layer, and a protective layer can be formed by sputtering. A soft magnetic supplemental layer also can be formed on the soft magnetic underlayer before forming the seed layer.

Abstract: A method of manufacturing magnetic recording media, comprising sequential steps of: (a) providing an apparatus for manufacturing the media; (b) supplying the apparatus with at least one substrate for the media; (c) forming a magnetic recording layer on the at least one substrate in a first portion of the apparatus, the magnetic recording layer including a surface; (d) treating the surface of the magnetic recording layer with an ionized oxygen-containing plasma in a second portion of the apparatus to form a plasma oxidized surface layer; and (e) forming a protective overcoat layer on the plasma oxidized surface layer of the magnetic recording layer in a third portion of the apparatus.

Abstract: A method for manufacturing a magnetic recording medium of the present invention includes a magnetic layer forming step in which a drying process is performed. The drying process includes: a pre-heating stage in which a magnetic coating film is heated until the surface temperature of the magnetic coating film stops rising and reaches a substantially constant temperature; a constant rate drying stage that is performed after the pre-heating stage in which the surface temperature of the magnetic coating film is held substantially constant; and a falling rate drying stage that is performed after the constant rate drying stage in which the surface temperature of the magnetic coating film is increased to be higher than the surface temperature during the constant rate drying stage to harden the magnetic coating film. The constant rate drying period in which the constant rate drying stage is performed is 0.2 seconds or more.

Abstract: A method of forming a magnetic assembly having at least one magnetic layer having dimensions of thickness, width and length, and at least one printable substrate layer having dimensions of thickness, width and length, including the steps of providing a molten magnetic composition including about 70 wt-% to about 95 wt-% of at least one magnetic material and about 5 wt-% to about 30 wt-% of at least one thermoplastic binder, forming the magnetic composition into a magnetic layer at an elevated temperature and directly applying the magnetic layer at an elevated temperature to a first surface of a printable substrate layer wherein. An adhesion promoting composition may be further provided between the magnetic layer and the printable substrate layer for improving adhesion between the magnetic layer and the printable substrate layer.

Abstract: The present invention relates to a method of producing a magnetic particle including forming a layer containing an alloy particle that can form CuAu type or Cu3Au type hard magnetic order alloy phase on a support, oxidizing the layer, and annealing the layer in non-oxidizing atmosphere. The invention also relates to a method of producing a magnetic particle including producing an alloy particle that can form hard magnetic order alloy phase, oxidizing the alloy particle, and annealing the particle in non-oxidizing atmosphere, and a magnetic particle produced by the foregoing production method. Further, the invention relates to a magnetic recording medium comprising a magnetic layer containing a magnetic particle and a method of producing a magnetic recording medium including forming a layer containing an alloy that can form the foregoing hard magnetic order alloy phase, oxidizing the layer, and annealing the layer in non-oxidizing atmosphere.

Abstract: A method for reducing noise in a lapping guide. Selected portions of a magnetoresistive device wafer are bombarded with ions such that a magnetoresistive effect of lapping guides is reduced. The device is lapped, using the lapping guides to measure an extent of the lapping.

Abstract: The present invention is to provide a method of fabricating a magnetic recording medium capable of forming a protective layer with a stable performance even in a case where a thickness thereof is as thin as 100 nm or less, and a magnetic recording medium fabricated by the method. A magnetic recording medium is fabricated in the following manner, that is, a magnetic layer having a ferromagnetic metal thin film having a thickness as thin as 100 nm or less is formed on one main surface of a long non-magnetic support, and on the magnetic layer, a protective layer containing carbon is formed by the chemical vapor deposition process using an ion source equipped with a hollow cathode.

Abstract: The object of the present invention is to provide an electromagnetic wave absorbing sheet excellent in permeability in high frequencies and to provide a method for manufacturing the same. The electromagnetic wave absorbing sheet of the present invention comprises insulating layers on the both sides of a magnetic layer. The magnetic layer is formed by densely depositing a large amount of magnetic powder such that the powder undergoes plastic deformation. Each magnetic powder is made to be a composite magnetic material formed of the soft magnetic metal phase consisting of a flaky soft magnetic metal powder and the insulating phase consisting of an insulating film formed on the surface of the soft magnetic metal phase. Additionally, another configuration can be taken in which a conductive layer is arranged on one of the insulating layers arranged on both sides of the magnetic layer, and the conductive layer is covered with an insulating layer.

Abstract: A method for producing a magnetic recording medium includes heat-curing a coated substrate to cure a non-magnetic back coat on the substrate and to cure a magnetic front coat on the substrate, and calendering the heat-cured coated substrate to produce the magnetic recording medium. The calendering optionally is off-line calendering during which the substrate passes between opposed, generally non-compliant rolls. Other methods, and magnetic recording media produced by the disclosed methods, also are disclosed.

Abstract: A manufacturing method for a spin valve sensor with a thin antiferromagnetic (AFM) layer exchange coupled to a self-pinned antiparallel coupled bias layer in the lead overlap regions is provided. The spin valve sensor comprises forming a ferromagnetic bias layer antiparallel coupled to a free layer in first and second passive regions where first and second lead layers overlap the spin valve sensor layers and forming a thin AFM layer exchange coupled to the bias layer to provide a pinning field to the bias layer. A cap layer is deposited over the thin AFM layer.

Abstract: A method for manufacturing a magnetic disk apparatus having a highly sensitive reproducing head. A spin-valve-type multilayer film composed of an antiferromagnetic layer, a ferromagnetic layer, a nonmagnetic layer and a free magnetic layer is used as a magnetoresistive-effect device for the reproducing head. An antiferromagnetic reaction layer is formed between the antiferromagnetic reaction layer and the ferromagnetic layer. The antiferromagnetic reaction layer is formed of a metallic compound containing oxygen.