There are provided a magnetoresistance effect element, a magnetic head, a magnetic head assembly and a magnetic recording system, which have high sensitivity and high reliability. The magnetoresistance effect element has two ferromagnetic layers, a non-magnetic layer provided between the ferromagnetic layers, and a layer containing an oxide or nitride as a principal component, wherein the layer containing the oxide or nitride as the principal component contains a magnetic transition metal element which does not bond to oxygen and nitrogen and which is at least one of Co, Fe and Ni.

Magnetoresistance effect element

An atomic layer deposition (ALD) process deposits thin films for microelectronic structures, such as advanced gap and tunnel junction applications, by plasma annealing at varying film thicknesses to obtain desired intrinsic film stress and breakdown film strength. The primary advantage of the ALD process is the near 100% step coverage with properties that are uniform along sidewalls. The process provides smooth (R a ˜2 Å), pure (impurities<1 at. %), AlO x films with improved breakdown strength (9–10 MV/cm) with a commercially feasible throughput.

Atomic layer deposition for fabricating thin films

A thin film magnetic head includes an upper shield section, a lower shield section and a magnetoresistance device section between the upper shield section and the lower shield section. The magnetoresistance device section is connected to the upper shield section and the lower shield section through conductive layers. Current flows through the magnetoresistance device section via the upper shield and the lower shield.

Thin film magnetic head

Methods are provided for forming uniformly thin layers in magnetic devices. Atomic layer deposition (ALD) can produce layers that are uniformly thick on an atomic scale. Magnetic tunnel junction dielectrics, for example, can be provided with perfect uniformity in thickness of 4 monolayers or less. Furthermore, conductive layers, including magnetic 12, 16 and non-magnetic layers 14, can be provided by ALD without spiking and other non-uniformity problems. The disclosed methods include forming metal oxide layers by multiple cycles of ALD and subsequently reducing the oxides to metal. The oxides tend to maintain more stable interfaces during formation.

Thin films for magnetic devices

The present invention relates to a device for diagnosing physiological state based on blood pulse waves detected in the body. It is the objective of the present invention to provide a device which correctly diagnoses the current physiological state based on changes in physiological state measured over a specified period of time in the past while taking into consideration the cyclical variation exhibited in physiological state. In order to realize this objective, the device according to the present invention has as its main components: blood pulse wave detector 381 and stroke-volume-per-beat measurer 382 which respectively detect blood pulse wave and stroke volume in the body; blood pulse wave extraction memory 386 which extracts characteristic information from the detected blood pulse wave; memory 383 in which the physiological state calculated from the stroke volume and this characteristic information is stored; output portion 385 which outputs an alarm; and microcomputer 387 which controls each part inside the device. The microcomputer calculates the circulatory parameters based on characteristic information obtained from the waveform extraction memory, and stores the parameters in memory at specified time intervals. At these times, microcomputer 387 calculates the circulatory parameters from the stroke volume per beat and the characteristic information of the blood pulse wave at specified time intervals, and stores the parameters in memory 383. Further, microcomputer 387 reads out from memory 383 the circulatory parameters from a specified time interval in the past, and calculates the average value and standard deviation. Microcomputer 387 then determines whether or not the current circulatory parameters are within a specified range determined by their average value and standard deviation. When the circulatory parameters are determined to be outside this range, microcomputer 387 controls output portion 385 to sound an alarm.

Device for diagnosing physiological state and device for controlling the same

PURPOSE: To obtain a narrow-track, low-noise magnetic head which has high mass-productivity and superior recording and reproducing characteristics by forming a magnetic core of a metallic magnetic body with high saturated magnetic flux density and combining it with a nonmagnetic protection material having high wear resistance. CONSTITUTION: A groove 42 for coil winding is formed in a surface 41 as the gap abutting surface of a block 40 made of nonmagnetic ferrite. Then, plural couples of adjacent grooves 43 and 43' are provided in parallel except at a nearly-V-shaped projection part at right angles to the coil winding groove 42. Then, the metallic magnetic body film 44 is deposited by sputtering over the entire surface of the projection part including the groove parts. Nonmagnetic material 45 is provided onto the obtained metallic magnetic body film 44 to fill at least the remaining groove parts. The unnecessary nonmagnetic material and metallic magnetic body film of the obtained block are removed to expose an operating gap formation surface made of the metallic body film with necessary track width (t). Nonmagnetic materials such as SiO 2 and glass are sputtered over gap formation surfaces of an obtained couple of core blocks 47 and 48 to necessary thickness to form gap formation films, and the couple of core blocks are butted against each other so that projection parts of metallic body films of the core blocks have prescribed track width and heated under pressure at the fusion temperature of the filling glass 45 to obtain a joined block 49. COPYRIGHT: (C)1984,JPO&Japio

Magnetic head and its manufacture

PURPOSE:To form a titled head suitable for recording and reproduction of a high-frequency signal to high coercive magnetic force recording medium, by using a pair of core block halves having a special construction for mutual butt planes CONSTITUTION:Mutual butt planes of the core block halves 31, 31' made of high permeability ferrite (such as Mn-Zn ferrite) are provided with projections 35, 35' (the top angle of the projections is about 45-90 deg, and the length of the ferrite at the tip of the projections toward the track width is about <=1/2 the track width), and metallic magnetic substance layers 30, 30' having higher magnetic flux density than that of the said ferrite and being made of high permeability material (such as Ni-Fe alloy) having about 0 magnetostriction, are formed on the projections The obtained core halves are butted to form an operating gap 32 and a nomagnetic filling agent (such as glass) is filled in a groove formed at both butt sections as a reinforcing material to form a core block (a caption 34 in the figure shows a window for coil winding)

Composite magnetic head and its manufacture

PURPOSE:To increase the accuracy for processing and to reduce the man-power, by providing a plurality of grooves on a block made of nonmagnetic substance, and a composite block where one or more metallic magnetic thin plates are inserted and fixed as one set in the grooves. CONSTITUTION:Grooves 35 are formed to a nonmagnetic substance block 34 made of Zn ferrite, metallic magnetic thin plates 10 made of an amorphous alloy, e.g. three sheets as one set, are inserted and fixed to the grooves 35 by applying an organic adhesive consisting essentially of epoxy system adhesive and acid anhydride system curing agent to form a block 36. Next, the block is cut at two-dot chain lines, a gap plane 28 is mirror-polished and a winding window groove 25 and a bonding groove 27 are processed. Next, track width restricting grooves 26, 26' are processed, and SiO2 being a gap member is coated on the plane 28 so that the SiO2 has a thickness a half the gap length with sputtering method to form magnetic core block halves 37, 37'. Next, a bonded block 38 is formed from the block halves by filling an adhesive 30 in the grooves 27, 26, 26' via a gap member. Finally, the two-dot chain lines are cut off to form the head.

Manufacture for magnetic head

PURPOSE:To prevent the formation of a quasi-operating gap so as to accomplish the recording and reproducing operations of high density by making a magnetic path partially of an amorphous magnetic material and by making a ferromagnetic ferrite partially of a non-magnetic material.

Magnetic head core

PURPOSE:To improve the stabilize head characteristics, by joining a metallic magnetic material directly to ferrite to reduce the variance in the dimensional accuracy between heads and characteristics. CONSTITUTION:A metallic magnetic material 34 is formed on the upper face of a large block 30, which should be the face facing a gap, by the sputtering method. The upper face of the large block is ground to remove the excess metallic magnetic material while leaving a metallic magnetic material 35 buried in a groove part 33 as it is. Grooves 37 are provided on both side parts of the metallic magnetic material left in the groove of a compound large block 36. Notched grooves 40 and 41 are provided in tip parts of worked small block pieces 38 and 39 (on the side of a head core facing a recording medium). Small block pieces 38 and 39 are so arranged that metallic magnetic material parts are matched to each other with a high precision, and a junction material 43 such as a glass is packed in the hole in the core front part formed by notched grooves, and core half bodies are joined to form a core block 42. The block is cut along dotted lines B and B' in the packed material part to take out many head cores. Thereafter, the face of the core facing the recording medium is finished to a prescribed gap depth and a prescribed front shape.

Takayuki Kumasaka

Papers

Magnetic head and its manufacture

Composite magnetic head and its manufacture

Manufacture for magnetic head

Magnetic head core

Compound magnetic head and its production