Abstract: There is provided a magnetoresistive head which can realize high sensitivity and low noise even when the reading track is being reduced. Longitudinal biasing is performed to a ferromagnetic free layer whose magnetization is rotated according to an external magnetic field by providing unidirectional magnetic anisotropy by exchange coupling to an antiferromagnetic layer. A hard magnetic film is arranged at the edge of a magnetoresistive film to reduce an effective reading track width.

Abstract: Replacing ruthenium with rhodium as the AFM coupling layer in a synthetically pinned CPP GMR structure enables the AP1/AP2 thicknesses to be increased. This results in improved stability and allows the free layer and AFM layer thicknesses to be decreased, leading to an overall improvement in the device performance. Another key advantage of this structure is that the magnetic annealing requirements (to establish antiparallelism between AP1 and AP2) can be significantly relaxed.

Abstract: Present invention provides enabling techniques of integrating novel nanotube elements into semiconductor devices, particularly in transistors, as gate channels or/and as interconnects. This is done in a series of process steps, which consist of fabricating magnetic-core-containing nanotubes of selected size (diameter and length), filtration of nanotube powders, preparing nanotube precursor in aqueous chemicals to form colloidal solutions of proper concentration, dispersing nanotube-containing solutions onto wafer surface, and finally positioning nanotubes at desired locations by magnetic means to complete nanotube device structure. The key to this invention is to provide miniature nanotubes with tangible physical properties, in this case, magnetic properties, so that they can be aligned, filtered, and precisely directed to desired locations for device application. Such processes enable nanotubes to be compatible with typical semiconductor wafer processing technologies.

Abstract: A method for refining the grain size of alloys which undergo ferromagnetic to paramagnetic phase transformation and an alloy produced therefrom. By subjecting the alloy to a timed application of a strong magnetic field, the temperature of phase boundaries can be shifted enabling phase transformations at lower temperatures.

Abstract: A perpendicular pressing/compacting method for a rare-earth alloy powder is provided to produce a sintered magnet with excellent magnetic properties. A method for pressing a rare-earth alloy powder by using a die is provided. The die is made of a non-magnetic material and has a die hole to define a cavity and a pair of yoke members provided on both sides of the cavity. The method includes the steps of: providing the rare-earth alloy powder; filling the cavity of the die with the rare-earth alloy powder; and compressing the rare-earth alloy powder, loaded in the cavity, between a pair of opposed press surfaces. A pulse magnetic field substantially perpendicular to a compressing direction is not applied until the apparent density of the rare-earth alloy powder in the cavity reaches a predetermined value, at least equal to 47% of the true density thereof, while the compressing step is being carried out.

Abstract: A device for magnetically annealing magnetoresistive elements formed on wafers includes a heated chuck and a delivery mechanism for individually placing the wafers individually on the chuck one at a time. A coil is adjacent to the chuck and generates a magnetic field after the wafer is heated to a Néel temperature of an anti-ferromagnetic layer. A control system regulates the temperature of the heated chuck, the strength of the magnetic field, and a time period during which each chuck is heated to control the annealing process. The annealed elements are incorporated in the fabrication of magnetic memory devices.

Abstract: A method for manufacturing magnetic sensing elements for use in magnetic sensors and hard disks. A ferromagnetic layer and a second antiferromagnetic layer are deposited on a nonmagnetic layer having a uniform thickness. The second antiferromagnetic layer is milled to form an indent. The resulting magnetic sensing element has a free magnetic layer reliably set in a single-magnetic-domain state in the track width direction.

Abstract: Coupling components to an underlying substrate using a composition of a polymer and magnetic material particles. Upon applying the composition between the component and the printed circuit board, the composition may be subjected to a magnetic field to align the magnetic material particles into a conductive path between the component and the underlying substrate. At the same time the polymer-based material may be cured or otherwise solidified to affix the conductive path formed by the magnetic material particles.

Abstract: A bulk amorphous metal inductive device comprises a magnetic core having at least one low-loss bulk ferromagnetic amorphous metal magnetic component forming a magnetic circuit having an air gap therein. The component comprises a plurality of similarly shaped layers of amorphous metal strips bonded together to form a polyhederally shaped part. The device has one or more electrical windings and is easily customized for specialized magnetic applications, e.g. for use as a transformer or inductor in power conditioning electronic circuitry employing switch-mode circuit topologies and switching frequencies ranging from 1 kHz to 200 kHz or more. The low core losses of the device, e.g. a loss of at most about 12 W/kg when excited at a frequency of 5 kHz to a peak induction level of 0.3 T, make it especially useful at frequencies of 1 kHz or more.

Abstract: A method for forming an NiCr seed layer based bottom spin valve sensor element having a synthetic antiferromagnet pinned (SyAP) layer and a capping layer comprising either a single specularly reflecting nano-oxide layer (NOL) or a bi-layer comprising a non-metallic layer and a specularly reflecting nano-oxide layer and the sensor element so formed. The method of producing these sensor elements provides elements having higher GMR ratios and lower resistances than elements of the prior art.

Abstract: A ferromagnetic resonator for use in a marker in a magnetomechanical electronic article surveillance system has improved magnetoresonant properties and/or reduced eddy current losses by virtue of being annealed so that the resonator has a fine domain structure with a domain width less than about 40 ÿm, or less than about 1.5 times the thickness of the resonator. This produces in the resonator an induced magnetic easy axis which is substantially perpendicular to the axis along which the resonator is operated magnetically by a magnetic bias element also contained in the marker.

Abstract: Thus, as shown by an exact electrodynamic computation of EMBF and the estimations described above of the velocity of turbulent flows arising due to their effect, application of amplitude- and frequency-modulated helically traveling (rotating and axially traveling) electromagnetic fields in metallurgical and chemical technologies and foundry can considerably increase the hydraulic efficiency of MHD facilities, intensify the processes of heat and mass transfer in technological plants, significantly increase their productivity, considerably decrease energy consumption for the production of metals, alloys, cast articles, and chemical products, and improve their quality.

Abstract: A method is provided for preserving the transverse biasing of a GMR (or MR) read head during back-end processing. In a first preferred embodiment, the method comprises magnetizing the longitudinal biasing layers of the read head in a transverse direction, so that the resulting field at the position of the transverse biasing layer places it in a minimum of potential energy which stabilizes its direction. The field of the longitudinal biasing layer is then reset to the longitudinal direction in a manner which maintains the transverse biasing direction. In a second embodiment, a novel fixture for mounting the read head during processing includes a magnetic portion which stabilizes the transverse bias of the read head. The two methods may be used singly or in combination.

Abstract: A specified amount of N2O or N2 is employed in a process gas of a DC magnetron for sputter depositing single or laminated films of NiFeCo—O—N or NiFeCo—N with a high uniaxial anisotropy HK after annealing these films along their hard axes. The films can be used for shield layers and/or pole piece layers in a magnetic head.

Abstract: In bottom spin valves of the lead overlay type the longitudinal bias field that stabilizes the device tends to fall off well before the gap is reached. This problem has been overcome by providing a manufacturing process that includes inserting an additional antiferromagnetic layer between the hard bias plugs and the overlaid leads. This additional antiferromagnetic layer and the lead layer are etched in the same operation to define the read gap, eliminating the possibility of misalignment between them. The extra antiferromagnetic layer is also longitudinally biased so there is no falloff in bias strength before the edge of the gap is reached. A process for manufacturing the device is also described.

Abstract: A GMR sensor comprising a sensor element having a spin valve configuration with a synthetic antiferromagnetic pinned layer and further comprising a ferromagnetic free layer biased by synthetic exchange biasing in a direction canted relative to the air bearing surface plane of the sensor. The resulting GMR sensor has a stable free layer domain structure, stable bias point and a wide dynamic range.

Abstract: A method using of a magnetic field to affect residual stress relief or phase transformations in a metallic material is disclosed. In a first aspect of the method, residual stress relief of a material is achieved at ambient temperatures by placing the material in a magnetic field. In a second aspect of the method, retained austenite stabilization is reversed in a ferrous alloy by applying a magnetic field to the alloy at ambient temperatures.

Abstract: Permanent magnet for voice coil actuator motors used to actuate head-arm assemblies in small form disk drives are produced from a dispersion of prealloyed rare earth magnetic particles in a thermoplastic binder. Upon shaping of green parts the magnetic axis of the particles is aligned with the field lines of a magnetic field. Following extraction of the binder the green parts are sintered to net shape. Improved magnetic properties, smaller dimensions, better than tolerances and 100% material utilization are claimed.

Abstract: As track density requirements for disk drives have grown more aggressive, GMR devices have been pushed to narrower track widths to match the track pitch of the drive width. Narrower track widths degrade stability, cause amplitude loss, due to the field originating from the hard bias structure, and side reading. This problem has been overcome in a process of manufacturing a device by adding an additional layer of soft magnetic material above the hard bias layers. The added layer provides flux closure to the hard bias layers thereby preventing flux leakage into the gap region. A non-magnetic layer must be included to prevent exchange coupling to the hard bias layers. In at least one embodiment the conductive leads are used to accomplish this.

Abstract: To avoid various problems caused by remnant magnetization and produce an anisotropic bonded magnet at a reduced cost, a method for producing an anisotropic bonded magnet by feeding a magnetic powder (such as an HDDR powder) into the cavity of a press machine and compacting it is provided. A weak magnetic field is created as a static magnetic field in a space including the cavity by using a magnetic member that is steadily magnetized. The magnetic powder being transported into the cavity is aligned parallel to the direction of the weak magnetic field. Next, the magnetic powder is compressed in the cavity, thereby obtaining a compact.

Abstract: Magnetic tunnel junction (MTJ) and charge perpendicular-to-plane (CPP) magnetic sensors are disclosed which have a first antiferromagnetic layer for pinning the magnetization direction in a pinned layer and a second antiferromagnetic layer for providing bias stabilization of a free layer. The two antiferromagnetic layers may be formed from the same material and using a spin-flop effect may be initialized simulataneously. A disk drive using these sensors is disclosed.

Abstract: A method of initializing a magnetic sensor having two antiferromagnetic layers is described. The method takes advantage of the spin flop effect such that the two antiferromagnetic layers may be orthogonally initialized. The signal polarity of the sensor is well controlled.

Abstract: A transducing head includes a first bias element, a second bias element, and a magnetoresistive sensor positioned between the first bias element and the second bias element. The first bias element and the second bias element are each formed of a permanent magnet material having a remanent magnetic moment in a range of about 200 to about 800 emu/cm3. In a preferred embodiment, the permanent magnet material is an alloy comprising iron, platinum, and at least one material selected from copper, silver, magnesium, lead, zinc, bismuth, and antimony.

Abstract: A magnetoresistive effect element (1) has an arrangement in which a pair of ferromagnetic material layers (magnetization fixed layer (5) and magnetization free layer (7)) is opposed to each other through an intermediate layer (6) to obtain a magnetoresistive change by causing a current to flow in the direction perpendicular to the layer surface and in which the ferromagnetic material layers are annealed by anneal including rotating field anneal and the following static field anneal. A magnetic memory device comprises this magnetoresistive effect element (1) and bit lines and word lines sandwiching the magnetoresistive effect element (1) in the thickness direction. When the magnetoresistive effect element (1) and the magnetic memory device are manufactured, the ferromagnetic material layers (5, 7) are annealed by rotating field anneal and the following static field anneal.

Abstract: A device for magnetically annealing magnetoresistive elements formed on wafers includes a heated chuck and a delivery mechanism for individually placing the wafers individually on the chuck one at a time. A coil is adjacent to the chuck and generates a magnetic field after the wafer is heated to a Néel temperature of an anti-ferromagnetic layer. A control system regulates the temperature of the heated chuck, the strength of the magnetic field, and a time period during which each chuck is heated to control the annealing process. The annealed elements are incorporated in the fabrication of magnetic memory devices.

Abstract: A method using of a magnetic field to affect residual stress relief or phase transformations in a metallic material is disclosed. In a first aspect of the method, residual stress relief of a material is achieved at ambient temperatures by placing the material in a magnetic field. In a second aspect of the method, retained austenite stabilization is reversed in a ferrous alloy by applying a magnetic field to the alloy at ambient temperatures.

Abstract: The invention is directed to a security element for the electronic surveillance of articles. This security element is detected by surveillance systems operating in different frequency ranges and it includes at least two materials of high permeability which, when excited by an external alternating magnetic field emit each a characteristic signal. The maximum signal components of the two materials lie in different frequency ranges and the signal components of the one material are negligibly ow in that particular frequency range in which the signal component of the other material is at a maximum level. The invention also relates to surveillance systems that incorporate these security elements.

Abstract: A magnetic alloy raw material is heated and melted to create a melt with floating said raw material by means of electromagnetic field from an inductive type heating coil. The melt is located in between a pair of cupper cooling plates driven by a solenoid coil, and then, splat-cooled below the peritectic point of the raw material by the cooling plates.

Abstract: A spin-valve thin-film magnetic element includes a substrate, a laminate formed on the substrate, biasing layers, and conductive layers. The laminate includes a free magnetic layer; a first nonmagnetic conductive layer, a first pinned magnetic layer and a first antiferromagnetic layer deposited on the upper surface, away from the substrate, of the free magnetic layer; a second nonmagnetic conductive layer, a second pinned magnetic layer and a second antiferromagnetic layer deposited on the lower surface, near the substrate, of the free magnetic layer. The biasing layers orients the magnetization vector of the free magnetic layer in a direction perpendicular to the magnetization vector of the pinned magnetic layers, and the conductive layers supplies a sensing current to the free magnetic layer. The first antiferromagnetic layer adjoining the first pinned magnetic layer fixes the magnetization vector of the first pinned magnetic layer in one direction.

Abstract: A ferromagnetic resonator for use in a marker in a magnetomechanical electronic article surveillance system is manufactured at reduced cost by being continuously annealed with a tensile stress applied along the ribbon axis and by providing an amorphous magnetic alloy containing iron, cobalt and nickel and in which the portion of cobalt is less than about 4 at %.

Abstract: A magnetic powder core comprises a molded article of a mixture of a glassy alloy powder and an insulating material. The glassy alloy comprises Fe and at least one element selected from Al, P, C, Si, and B, and has a texture primarily composed of an amorphous phase. The glassy alloy exhibits a temperature difference &Dgr;Tx, which is represented by the equation &Dgr;Tx=Tx−Tg, of at least 20 K in a supercooled liquid, wherein Tx indicates the crystallization temperature and Tg indicates the glass transition temperature. The magnetic core precursor is produced mixing the glassy alloy powder with the insulating material, compacting the mixture to form a magnetic core precursor, and annealing the magnetic core precursor at a temperature in the range between (Tg−170) K and Tg K to relieve the internal stress of the magnetic core precursor. The glassy alloy exhibits low coercive force and low core loss.

Abstract: As track density requirements for disk drives have grown more aggressive, GMR devices have been pushed to narrower track widths to match the track pitch of the drive width. Narrower track widths degrade stability, cause amplitude loss, due to the field originating from the hard bias structure, and side reading. This problem has been overcome by adding an additional layer of soft magnetic material above the hard bias layers. The added layer provides flux closure to the hard bias layers thereby preventing flux leakage into the gap region. A non-magnetic layer must be included to prevent exchange coupling to the hard bias layers. In at least one embodiment the conductive leads are used to accomplish this. A process for manufacturing the device is also described.

Abstract: Disclosed are methods for producing compositionally modified sintered RE—Fe—B-based rare earth permanent magnets, by the addition of small amounts of Nd, Cu, Ti, Nb, or other transition metals, and mixtures thereof, to maximize fracture toughness with corresponding improved machinability, while maintaining maximum energy product, said method comprising the steps of:

Abstract: A method for fabricating a longitudinally hard biased, bottom spin valve GMR sensor with a lead overlay (LOL) conducting lead configuration and a narrow effective trackwidth. The advantageous properties of the sensor are obtained by providing two novel barrier layers, one of which prevents oxidation of and Au diffusion into the free layer during annealing and etching and the other of which prevents oxidation of the capping layer during annealing so as to allow good electrical contact between the lead and the sensor stack.

Abstract: A dual spin valve (SV) sensor is provided with a longitudinal bias stack sandwiched between a first SV stack and a second SV stack. The longitudinal bias stack comprises an antiferromagnetic (AFM) layer sandwiched between first and second ferromagnetic layers. The first and second SV stacks comprise antiparallel (AP)-pinned layers pinned by AFM layers made of an AFM material having a higher blocking temperature than the AFM material of the bias stack allowing the AP-pinned layers to be pinned in a transverse direction and the bias stack to be pinned in a longitudinal direction. The demagnetizing fields of the two AP-pinned layers cancel each other and the bias stack provides flux closures for the sense layers of the first and second SV stacks.

Abstract: Patterned, longitudinally and transversely antiferromagnetically exchange biased GMR sensors are provided which have narrow effective trackwidths and reduced side reading. The exchange biasing significantly reduces signals produced by the portion of the ferromagnetic free layer that is underneath the conducting leads while still providing a strong pinning field to maintain sensor stability. In the case of the transversely biased sensor, the magnetization of the free and biasing layers in the same direction as the pinned layer simplifies the fabrication process and permits the formation of thinner leads by eliminating the necessity for current shunting.

Abstract: A magnetic sensing element having a reduced electrical resistance and a large exchange anisotropic magnetic field between a free layer and antiferromagnetic layers for exchange biasing is provided. The magnetic sensing element includes second antiferromagnetic layers and a free magnetic layer, and the length of the second antiferromagnetic layers in a height direction in side regions disposed at the lateral sides of a track width region is larger than the length of the free magnetic layer in the height direction in the track width region.

Abstract: A magnetic read head with reduced side reading characteristics is described. This design combines use of a current channeling layer (CCL) with stabilizing longitudinal bias layers whose magnetization direction is canted relative to that of the free layer easy axis and that of the pinned layer (of the GMR). This provides several advantages: First, the canting of the free layer at the side region results in a reduction of side reading by reducing magnetic sensitivity in that region. Second, the CCL leads to a narrow current flow profile at the side region, therefore producing a narrow track width definition. A process for making this device is described. Said process allows some of the requirements for interface cleaning associated with prior art processes to be relaxed.

Abstract: In bottom spin valves of the lead overlay type the longitudinal bias field that stabilizes the device tends to fall off well before the gap is reached. This problem has been overcome by inserting an additional antiferromagnetic layer between the hard bias plugs and the overlaid leads. This additional antiferromagnetic layer and the lead layer are etched in the same operation to define the read gap, eliminating the possibility of misalignment between them. The extra antiferromagnetic layer is also longitudinally biased so there is no falloff in bias strength before the edge of the gap is reached. A process for manufacturing the device is also described.

Abstract: A patterned, synthetic, longitudinally exchange biased GMR sensor is provided which has a narrow effective trackwidth and reduced side reading. The advantageous properties of the sensor are obtained by satisfying a novel relationship between the magnetizations (M) of the ferromagnetic free layer (F1) and the ferromagnetic biasing layer (F2) which enables the optimal thicknesses of those layers to be determined for a wide range of ferromagnetic materials and exchange coupling materials. The relationship to be satisfied is MF2/MF1=(Js+Jex)/Js, where Js is the synthetic coupling energy between F1 and F2 and Jex is the exchange energy between F2 and an overlaying antiferromagnetic pinning layer. An alternative embodiment omits the overlaying antiferromagnetic pinning layer which causes the relationship to become MF2/MF1=1.

Abstract: A method for refining the grain size of alloys which undergo ferromagnetic to paramagnetic phase transformation and an alloy produced therefrom. By subjecting the alloy to a timed application of a strong magnetic field, the temperature of phase boundaries can be shifted enabling phase transformations at lower temperatures. 1 Applicants: Jayoung Koo Shiun Ling Michael J. Luton Hans Thomann Narasimha-Rao V.

Abstract: The present invention provides a powder compacting apparatus including: a die having a through hole forming a cavity; a first punch and a second punch for pressing a rare-earth alloy magnetic powder filled in the cavity; and a magnetic field generator for applying an orientation magnetic field parallel to a pressing direction through the rare-earth alloy magnetic powder in the cavity, wherein at least one of the first and second punches and has a curved pressing surface, and the pressing surface is given a shape such as to suppress the movement of particles of the rare-earth alloy magnetic powder along the pressing surface during the pressing step.

Abstract: A method for forming an NiCr seed layer based bottom spin valve sensor element having a synthetic antiferromagnet pinned (SyAP) layer and a capping layer comprising either a single specularly reflecting nano-oxide layer (NOL) or a bi-layer comprising a non-metallic layer and a specularly reflecting nano-oxide layer and the sensor element so formed. The method of producing these sensor elements provides elements having higher GMR ratios and lower resistances than elements of the prior art.

Abstract: First and second magneto-resistive effect elements (1) and (2) of a current perpendicular to plane type having magnetic flux sensing films are laminated through a nonmagnetic intermediate gap layer (3) in such a manner that their magnetic flux sensing films are located close to each other. Then, magneto-resistive change characteristics are caused to become opposite to each other so that a differential output between the output of the first and second magneto-resistive effect elements may be generated as a magnetic sensor output or a differential output between the output of the first and second magneto-resistive effect elements may be generated as a differential output in an external circuit configuration. In this manner, a resolution can be improved by a configuration in which a gap length, which decides a resolution, may not be restricted by a thickness of a magneto-resistive effect element. Therefore, restrictions imposed on the resolution in the MR magnetic sensor can be improved.

Abstract: A method of initializing a magnetic sensor having two antiferromagnetic layers is described. The method takes advantage of the spin flop effect such that the two antiferromagnetic layers may be orthogonally initialized. The signal polarity of the sensor is well controlled.

Abstract: A ferromagnetic resonator for use in a marker in a magnetomechanical electronic article surveillance system has improved magnetoresonant properties and/or reduced eddy current losses by virtue of being annealed so that the resonator has a fine domain structure with a domain width less than about 40 &mgr;m, or less than about 1.5 times the thickness of the resonator. This produces in the resonator an induced magnetic easy axis which is substantially perpendicular to the axis along which the resonator is operated magnetically by a magnetic bias element also contained in the marker.

Abstract: A method for fabricating a single top spin valve head that is capable of reading ultra-high density recordings. Said top spin valve has a CoFe free layer for high GMR ratio, which is grown on a NiCr/Ru layer to provide better magnetic properties and has a ferromagnetically coupled CoFe/NiCr/CoFe laminated pinned layer for thermal stability and robustness.

Abstract: In order to dampen magnetization changes in magnetic devices, such as magnetic tunnel junctions (MTJ) used in high speed Magnetic Random Access Memory (MRAM), a transition metal selected from the 4d transition metals and 5d transition metals is alloyed into the magnetic layer to be dampened. In a preferred form, a magnetic permalloy layer is alloyed with osmium (Os) in an atomic concentration of between 4% and 15% of the alloy.

Abstract: A heat-conductive sheet comprising a cured or semi-cured binder wherein a carbon fiber is orientated in the direction of the thickness of the heat-conductive sheet. This heat-conductive sheet exhibits a high anisotropic heat conductivity along the direction of the thickness thereof to thereby enable efficiently releasing heat from a heating element such as a semiconductor element or semiconductor package. Moreover, the heat-conductive sheet is excellent in not only heat resistance, durability and mechanical strength but also adherence to the heating element.

Abstract: Devices and methods employ FeGa alloys having excellent magnetostriction and good strength. Additionally, methods of producing preferentially oriented FeGa alloys are described.