Tdk Corporation

Sae Magnetics (h.k.) Limited

Yoshiyuki Mizoguchi

Hiroshi Yamazaki

Nobuya Oyama

Kunihiro Ueda

Suguru Watanabe

Soji Koide

Hiraku Hirabayashi

Tsuyoshi Umehara

Hiroki Matsukuma

Kazuhide Yamada

Norikazu Ota

Katsumichi Tagami

Satoshi Abe

Homare Tokida

Yuji Ito

Naoki Ohta

Naoto Matono

Takahiro Imai

Noboru Yamanaka

Hideaki Sato

Nozomu Hachisuka

Kazuhiko Maejima

Toshiyuki Ayukawa

Eric Cheuk Wing Leung

Chris Chiu Ming Leung

Leo Wai Kay Lau

Charles Kin Chiu Wong

A magnetic sensor is provided with first and second magnetoresistive effect elements that can detect an external magnetic field. The first and second magnetoresistive effect elements are a plurality of layers of multilayer body including free layers where their magnetization directions vary due to the external magnetic field. Shapes of the first and second magnetoresistive effect elements viewed from the upper side in the lamination direction are different from each other. The first magnetoresistive effect element has a shape that can increase a slope of an output of the first magnetoresistive effect element relative to the change of the external magnetic field. The second magnetoresistive effect element has a shape that can decrease a slope of an output of the second magnetoresistive effect element relative to the change of the external magnetic field compared to the slope of the output of the first magnetoresistive effect element.

Magnetic sensor and magnetic encoder

A sensor system according to an embodiment of the disclosure includes a physical quantity distribution generation source configured to generate a distribution of a physical quantity, and a plurality of sensor packages including respective sensor chips configured to detect the physical quantity. In a plane including the sensor packages, central positions of the respective sensor chips are shifted in directions from central positions of the respective sensor packages toward a central position of the distribution of the physical quantity, and distances from the central position of the distribution of the physical quantity to the central positions of the respective sensor chips of the respective sensor packages are substantially equal to each other.

Sensor system, sensor module, and method of mounting sensor system

A magnetic sensor is provided with first and second magnetoresistive effect elements that can detect an external magnetic field. The first and second magnetoresistive effect elements include at least magnetization direction change layers where a direction of magnetization is changed according to an external magnetic field. The width Wof a magnetization direction change layer in an initial magnetization direction of the magnetization direction change layer of the first magnetoresistive effect element, and the width Wof a magnetization direction change layer in an initial magnetization direction of the magnetization direction change layer of the second magnetoresistive effect element have a relationship shown by formula (1) below. Sensitivity of the first magnetoresistive effect element to the external magnetic field is higher than that of the second magnetoresistive effect element.&#x2003;&#x2003;(1)

A magnetic sensor includes an MR element and a bias field generation unit. The MR element includes a magnetization pinned layer having a magnetization pinned in a direction parallel to an X direction, a free layer having a magnetization that varies depending on an X-direction component of an external magnetic field, and a nonmagnetic layer interposed between the magnetization pinned layer and the free layer. The magnetization pinned layer, the nonmagnetic layer and the free layer are stacked to be adjacent in a Y direction. The free layer receives an interlayer coupling magnetic field in a direction parallel to the X direction resulting from the magnetization pinned layer. The bias field generation unit applies a bias magnetic field to the free layer. The bias magnetic field includes a first component in a direction opposite to that of the interlayer coupling magnetic field and a second component in a Z direction.

Magnetic sensor with reduced effect of interlayer coupling magnetic field

A magnetic sensor includes an MR element and a pair of magnets. The MR element includes a magnetization pinned layer having a magnetization pinned in a direction parallel to an X direction, a free layer having a magnetization that varies depending on an X-direction component of an external magnetic field, and a nonmagnetic layer interposed between the magnetization pinned layer and the free layer. The magnetization pinned layer, the nonmagnetic layer and the free layer are stacked to be adjacent in a Y direction. The free layer receives an interlayer coupling magnetic field in a direction parallel to the X direction resulting from the magnetization pinned layer. The pair of magnets applies a bias magnetic field to the free layer. The bias magnetic field includes a first component in a direction opposite to that of the interlayer coupling magnetic field and a second component in a Z direction.

A method of forming a thin-film magnetic head comprises a lower magnetic pole layer forming step of forming a lower magnetic pole layer; a lower magnetic pole projection forming step of forming the lower magnetic pole layer with a lower magnetic pole projection; a gap layer forming step of laminating a nonmagnetic gap layer on the lower magnetic pole projection; and an upper magnetic pole forming step of forming an upper magnetic pole on the nonmagnetic gap layer. The lower magnetic pole projection forming step forms the lower magnetic pole projection by simultaneously etching an area including parts adjacent to a part to become the lower magnetic pole projection on both sides in a track width direction and a part adjacent to the part to become the lower magnetic pole projection on the side opposite from a medium-opposing surface in a surface of the lower magnetic pole layer.

Method of manufacturing a thin-film magnetic head having a lower magnetic pole projection projecting toward an upper magnetic pole

A multi-channel head includes a substrate, a plurality of write elements arranged in a track width direction above the substrate in a lamination direction, and a plurality of read elements arranged in the track width direction above the plurality of write elements in the lamination direction. At least one of the plurality of write elements is offset from the others in the lamination direction. All the plurality of read elements are located higher than an uppermost one of the plurality of write elements in the lamination direction.

Multi-channel head

Provided is a multichannel thin-film magnetic head having a plurality of read head elements neighboring with each other, each of which includes shield layers having a desired stable magnetic-domain structure. The head comprises at least one read head part comprising a plurality of read head elements aligned in the track width direction, wherein each of the plurality of read head elements comprises a lower shield layer and an upper shield layer, and the at least one read head part comprises: a lower shield part comprising a plurality of the lower shield layers aligned in the track width direction; and an upper shield part comprising a plurality of the upper shield layers aligned in the track width direction, and wherein dummy shield layers are provided respectively on both sides of at least the lower shield part.

Multichannel thin-film magnetic head with dummy shields

Provided is a method for testing a head element that enables proper evaluation of the head element based on a characteristic of the head element under high-temperature and high-stress conditions. The testing method can be performed on a thin-film magnetic head including a head element and a heating element capable of applying a heat and stress to the head element, or performed on a row bar or a substrate wafer on which a plurality of the head elements and a plurality of the heating elements are disposed. The testing method comprises the steps of: causing the heating element to generate heat to apply a heat and stress to the head element; and measuring a characteristic of the head element under the heat and stress to evaluate the head element.

Testing method of head element and magnetic recording and reproducing apparatus capable of head evaluating

A method of producing a thin film magnetic head includes the steps of: forming a second lower magnetic pole layer in a part on a first lower magnetic pole layer; forming, over the entire wafer surface, an insulating layer so as to be thicker than the thickness of the second lower magnetic pole layer in the stacking direction, the insulating layer being less likely to be etched than the second lower magnetic pole layer; carrying out a planarizing process by CMP on the entire wafer surface until the second lower magnetic pole layer is exposed; forming a concave portion including the second lower magnetic pole layer and the insulating layer by ion beam etching on the entire wafer surface; forming a recording gap layer over the entire wafer surface; and forming a first upper magnetic pole layer in the upper magnetic pole layer so as to fill the concave portion.

Method of producing thin film magnetic head

The present invention relates to a thin-film magnetic head with a heater. A thin-film magnetic head includes a substrate, a magnetic read head element that has a shield area and is formed on the substrate, a magnetic write head element that has a pole area and is formed on the opposite side of the substrate with respect to the magnetic read head element, an overcoat layer that covers the magnetic read head element and the magnetic write head element and is formed on the substrate, a heater that heats at least during the magnetic read head element or the magnetic write head element in operation and is formed in the overcoat layer, and a slit area that splits the shield area in a shield length direction and is made of lower thermal conductivity material than the one of the shield area.

Thin-film magnetic head with heater spaced further from medium facing surface than split in shield

A thin-film magnetic head according to the present invention comprises: a substrate; at least one magnetic head element formed on the substrate; an overcoat multilayer composed of a plurality of overcoat layers, formed on the substrate so as to cover the at least one magnetic head element; and at least one heating element to be heated at least during operation of the at least one magnetic head element, the at least one heating element provided in the overcoat multilayer, and a coefficient of thermal expansion of an overcoat layer located farthest from the substrate in the overcoat multilayer being smaller than a coefficient of thermal expansion of an overcoat layer located closest to the substrate in the overcoat multilayer.

Thin-film magnetic head with heater in overcoat multilayer, head gimbal assembly with thin-film magnetic head, and magnetic disk drive apparatus with head gimbal assembly

A method is presented for grinding a surface of an elongate bar having a plurality of thin film magnetic elements aligned in a line, each of the thin film magnetic elements having a magnetoresistive sensor for reading a magnetic record from a recording medium and an inductive electromagnetic transducer for writing a magnetic record into the recording medium in a stacked structure, the surface of the bar being a grind surface so that it can be formed into an air-bearing surface by means of the grinding. The method has steps of providing first resistive films on the grind surface in advance along a first longitudinal line parallel to a longitudinal direction of the bar, and providing second resistive films on the grind surface in advance along a second longitudinal line parallel to the longitudinal direction of the bar. The method further has a step of grinding the grind surface while pressing the bar against a rotating grinding disc with the longitudinal direction of the bar positioned toward a radial direction of the grinding disc, measuring electric resistance values of the first and second resistive films, and controlling an amount that is ground of the grind surface in the longitudinal direction and a direction perpendicular to the longitudinal direction based on the electric resistance values of the first resistive film and the second resistive films.

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Tokyo, Japan

Yoshiyuki Mizoguchi