Detail Of Free Layer Or Additional Film For Affecting Or Biasing The Free Layer Patents (Class 360/324.12)
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Patent number: 7287313Abstract: 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.Type: GrantFiled: June 30, 2005Date of Patent: October 30, 2007Assignee: Headway Technologies, Inc.Inventors: Yimin Guo, Li-Yan Zhu
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Patent number: 7289303Abstract: Magnetoresistive (MR) sensors are disclosed having mechanisms for reducing edge effects such as Barkhausen noise. The sensors include a pinned layer and a free layer with an exchange coupling layer adjoining the free layer, and a ferromagnetic layer having a fixed magnetic moment adjoining the exchange coupling layer. The exchange coupling layer and ferromagnetic layer form a synthetic antiferromagnetic structure with part of the free layer, providing bias that reduces magnetic instabilities at edges of the free layer. Such synthetic antiferromagnetic structures can provide a stronger bias than conventional antiferromagnetic layers, as well as a more exactly defined track width than conventional hard magnetic bias layers. The synthetic antiferromagnetic structures can also provide protection for the free layer during processing, in contrast with the trimming of conventional antiferromagnetic layers that exposes if not removes part of the free layer.Type: GrantFiled: April 5, 2001Date of Patent: October 30, 2007Assignee: Western Digital (Fremont), LLCInventors: Kyusik Sin, Ningjia Zhu, Yingjian Chen
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Patent number: 7284316Abstract: A method for forming a hard bias structure in a magnetoresistive sensor is disclosed. A magnetoresistive sensor having a soft magnetic bias layer, spacer layer, and a magnetoresistive layer, is formed over a substrate having a gap layer. A mask is formed over a portion of the magnetoresistive sensor structure to define a central region. The masked structure is ion milled to remove portions not shielded by the mask, to form the central region with sloped sides, and to expose a region of the gap layer laterally adjacent the sloped sides. A first underlayer is deposited onto at least the sloped sides at a high deposition angle. A second underlayer is deposited to at least partially overlap the first underlayer, and at a first lower deposition angle. A hard bias layer is deposited over at least a portion of the second underlayer, and at a second lower deposition angle.Type: GrantFiled: November 17, 2004Date of Patent: October 23, 2007Assignee: Western Digital (Fremont), LLCInventors: Yiming Huai, Jinqiu Zhang, Jing Zhang
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Patent number: 7286329Abstract: A magnetic sensor is disclosed having a shallow contiguous junction. Such a sensor is can greatly increase yield for mass-produced heads, especially for large wafers. The magnetic bias layers can be aligned with a free layer of the sensor, improving performance. Milling may be terminated prior to penetration of an antiferromagnetic layer, so that for example the antiferromagnetic layer may extend significantly beyond the free and pinned layers of the sensor.Type: GrantFiled: February 27, 2004Date of Patent: October 23, 2007Assignee: Western Digital (Fremont), LLCInventors: Yingjian Chen, Wei Zhang, Mohamad T. Krounbi, Satoru Araki, Jinqiu Zhang
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Publication number: 20070242396Abstract: In an MR element, each of a pinned layer and a free layer includes a Heusler alloy layer. The Heusler alloy layer has two surfaces that are quadrilateral in shape and face toward opposite directions. The Heusler alloy layer includes one crystal grain that touches four sides of one of the two surfaces. In a method of manufacturing the MR element, a layered film to be the MR element is formed and patterned, and then heat treatment is performed on the layered film patterned, so that crystal grains included in a film to be the Heusler alloy layer in the layered film grow and one crystal grain that touches four sides of one of the surfaces of the film to be the Heusler alloy layer is thereby formed.Type: ApplicationFiled: March 8, 2007Publication date: October 18, 2007Applicant: TDK CORPORATIONInventors: Koji Shimazawa, Yoshihiro Tsuchiya, Tomohito Mizuno, Daisuke Miyauchi, Shinji Hara, Takahiko Machita
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Patent number: 7283336Abstract: A method and apparatus for providing a current-in-plane (CIP) GMR sensor with an improved in-stack bias layer with a thinner sensor stack is disclosed. Improved pinning of a free-layer in a CIP GMR sensor stack is provided using dual in-stack biasing layers. The sensor stack is made thin because an anti-ferromagnetic layer is not necessary to bias the free-layer.Type: GrantFiled: March 29, 2004Date of Patent: October 16, 2007Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventor: Hardayal Singh Gill
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Patent number: 7283337Abstract: A hard bias (HB) structure for biasing a free layer in a MR sensor within a magnetic read head is comprised of a main biasing layer with a large negative magnetostriction (?S) value. Compressive stress in the device after lapping induces a strong in-plane anisotropy that effectively provides a longitudinal bias to stabilize the sensor. The main biasing layer is formed between two FM layers, and at least one AFM layer is disposed above the upper FM layer or below the lower FM layer. Additionally, there may be a Ta/Ni or Ta/NiFe seed layer as the bottom layer in the HB structure. Compared with a conventional abutted junction exchange bias design, the HB structure described herein results in higher output amplitude under similar asymmetry sigma and significantly decreases sidelobe occurrence. Furthermore, smaller MRWu with a similar track width is achieved since the main biasing layer acts as a side shield.Type: GrantFiled: March 4, 2005Date of Patent: October 16, 2007Assignee: Headway Technologies, Inc.Inventors: Masanori Sakai, Kunliang Zhang, Kenichi Takano, Chyu-Jiuh Torng, Yunfei Li, Po-Kang Wang
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Patent number: 7283334Abstract: A magnetic head having a spin valve sensor that is fabricated utilizing an Al2O3, NiMnO, NiFeCr seed layer upon which a typical PtMn spin valve sensor layer structure is subsequently fabricated. The preferred embodiment fabrication process of the NiFeCr layer includes the overdeposition of the layer to a first thickness of from 15 ? to 45 ? followed by the etching back of the seed layer of approximately 5 ? to approximately 15 ? to its desired final thickness of approximately 10 ? to 40 ?. The Cr at. % composition in the NiFeCr layer is preferably from approximately 35 at. % to approximately 46 at. %. The crystal structure of the surface of the etched back NiFeCr layer results in an improved crystal structure to the subsequently fabricated spin valve sensor layers, such that the fabricated spin valve exhibits increased ?R/R and reduced coercivity.Type: GrantFiled: June 15, 2006Date of Patent: October 16, 2007Assignee: International Business Machines CorporationInventor: Mustafa Pinarbasi
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Patent number: 7283335Abstract: In a magnetic detecting element, ferromagnetic layers are formed on both side portions of a free magnetic layer through nonmagnetic intermediate layers, and second antiferromagnetic layers are formed on the ferromagnetic layers with a spacing greater than the spacing between the ferromagnetic layers in the track width direction. Also, in both side portions of the element, the ferromagnetic layers have portions extending from the inner end surfaces of the respective second antiferromagnetic layers toward the center in the track width direction. Furthermore, electrode layers are formed on the second antiferromagnetic layers and on the extending portions of the ferromagnetic layers. It is thus possible to improve reproduced output, and suppress widening of an effective reproducing track width to appropriately suppress the occurrence of side reading.Type: GrantFiled: May 6, 2003Date of Patent: October 16, 2007Assignee: Alps Electric Co., LtdInventors: Naoya Hasegawa, Eiji Umetsu
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Patent number: 7280325Abstract: A CPP magnetic sensor is disclosed with a ferromagnetic layer that extends in a first direction a first distance; a nonferromagnetic spacer layer that adjoins the ferromagnetic layer and extends in the first direction a second distance that is substantially equal to the first distance; and a ferromagnetic structure that is separated from the ferromagnetic layer by the spacer layer, the ferromagnetic structure having a first section that extends in the first direction a third distance that is substantially equal to the second distance, the ferromagnetic structure having a second section that is disposed further than the first section from the spacer layer, the second section extending at least twice as far as the first section in the first direction. The ferromagnetic structure can be used for in-stack bias or pinning of free or pinned layers, respectively, and side shields can be provided for high areal density.Type: GrantFiled: March 31, 2004Date of Patent: October 9, 2007Assignee: Western Digital (Fremont), LLCInventor: Tao Pan
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Patent number: 7280324Abstract: A magnetoresistive sensor having improved free layer biasing and track width control.Type: GrantFiled: February 17, 2004Date of Patent: October 9, 2007Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventor: Hardayal Singh Gill
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Patent number: 7280326Abstract: A current perpendicular to plane (CPP) GMR sensor having first and second outer pinned layers and a trilayer free layer therebetween. The free layer includes first and second outer magnetic layers, and a partially oxidized magnetic layer disposed there between. The middle partially oxidized layer is antiparallel coupled with the outer magnetic layers of the free layer by first and second coupling layers which prevent oxygen migration from the central layer into the outer magnetic layers of the free layer. The partial oxidation of the middle layer provides a limited amount of electrical resistance at a desired location within the free layer to increase GMR.Type: GrantFiled: July 30, 2004Date of Patent: October 9, 2007Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventor: Hardayal Singh Gill
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Publication number: 20070230070Abstract: A pinned layer of an MR element includes an underlying magnetic layer made of a magnetic alloy layer having a body-centered cubic structure, and a Heusler alloy layer formed on the underlying magnetic layer. A free layer of the MR element includes an underlying magnetic layer made of a magnetic alloy layer having a body-centered cubic structure, and a Heusler alloy layer formed on the underlying magnetic layer. Each of these two Heusler alloy layers is made of a CoMnSi alloy having an Mn content higher than 25 atomic percent and lower than or equal to 40 atomic percent, and contains a principal component having a B2 structure in which Co atoms are placed at body-centered positions of unit cells and Mn atoms or Si atoms are randomly placed at vertexes of the unit cells.Type: ApplicationFiled: February 22, 2007Publication date: October 4, 2007Applicant: TDK CORPORATIONInventors: Tomohito Mizuno, Yoshihiro Tsuchiya
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Patent number: 7277261Abstract: A magneto-resistance effect head is provided with a lower conductive layer which is provided with a recessed portion, and a vertical bias layer is provided in the recessed portion. A free layer is provided on the lower conductive layer. On the free layer, layered in the following order are the non-magnetic layer, the fixed layer, the fixing layer, and the upper layer so as not to be placed immediately above the vertical bias layer. Furthermore, an upper conductive layer is provided on the upper layer and an insulation layer. In the direction of the magnetic field applied by the vertical bias layer, the free layer is made greater in length than the fixed layer and the free layer is disposed in proximity to the vertical bias layer with the distance between the fixed layer and the vertical bias layer remaining unchanged.Type: GrantFiled: June 30, 2006Date of Patent: October 2, 2007Assignee: NEC CorporationInventors: Kazuhiko Hayashi, Junichi Fujikata, Tsutomu Ishi, Shigeru Mori, Keishi Ohashi, Masafumi Nakada, Kivokazu Nagahara, Kunihiko Ishihara, Nobuyuki Ishiwata
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Patent number: 7277260Abstract: A magnetic head that includes a spin valve sensor of the present invention which may be a CIP or CPP device. The sensor includes a free magnetic layer that is comprised of CoFeCu. In certain embodiments the free magnetic layer may also include a sublayer of NiFe. The CoFeCu free magnetic layer preferably includes Fe in a range of 5-20 at. % and Cu in a range of 1-10 at. %. The sensor may also include a cap layer of the present invention that is comprised of ZnOx/TaOx. The CoFeCu free magnetic layer of the present invention provides improved sensor performance characteristics of reduced coercivity and generally similar GMR as compared to the prior art. Where the ZnOx/TaOx cap layer is utilized, increased GMR is obtained. Thus a magnetic head of the present invention that includes both a CoFeCu free magnetic layer and a ZnOx/TaOx cap layer demonstrates reduced coercivity and increased GMR.Type: GrantFiled: September 21, 2004Date of Patent: October 2, 2007Assignee: Hitachi Global Storage Technologies Netherlands, B.V.Inventors: Hardayal Singh Gill, Alexander M. Zeltser
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Patent number: 7274542Abstract: A magnetic sensor includes a spacer having at least a nonmagnetic metal layer inserted between the upper shield layer and the longitudinal bias layers or between the upper shield layer and the longitudinal bias layers plus the magnetoresistive film, the shortest distance between the longitudinal bias layers and the free layer of the magnetoresistive film is set smaller than the shortest distance between the longitudinal bias layers and the upper shield layer, and this arrangement ensures that the amount of magnetic flux entering the magnetoresistive film from the longitudinal bias layers is larger than that absorbed by the upper shield layer, thus realizing a magnetic sensor whose Barkhausen noise is suppressed.Type: GrantFiled: February 5, 2003Date of Patent: September 25, 2007Assignee: Hitachi Global Storage Technologies Japan, Ltd.Inventors: Taku Shintani, Katsuro Watanabe, Masahiko Hatatani, Kikuo Kusukawa
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Publication number: 20070217087Abstract: A magnetic thin film has a layer which is formed of an alloy having a ordered crystal structure whose composition formula is represented by XYZ or X2YZ (where X is one or more than one of the elements selected from the group consisting of Co, Ir, Rh, Pt, and Cu, Y is one or more than one of the elements selected from the group consisting of V, Cr, Mn, and Fe, and Z is one or more than one of the elements selected the group consisting of Al, Si, Ge, As, Sb, Bi, In, Ti, and Pb). The alloy contains at least one additive element which is not included in the composition formula of the alloy and which has a Debye temperature that is equal to or less than 300K.Type: ApplicationFiled: March 16, 2007Publication date: September 20, 2007Applicant: TDK CorporationInventors: Kei Hirata, Keita Kawamori, Tomohito Mizuno, Yoshihiro Tsuchiya, Koji Shimazawa
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Patent number: 7270896Abstract: A magnetic tunneling element is constructed from a MgO or Mg—ZnO tunnel barrier and an amorphous magnetic layer in proximity with the tunnel baffler. The amorphous magnetic layer includes Co and at least one additional element selected to make the layer amorphous. Magnetic tunnel junctions formed from the amorphous magnetic layer, the tunnel barrier, and an additional ferromagnetic layer have tunneling magnetoresistance values of up to 200% or more.Type: GrantFiled: July 2, 2004Date of Patent: September 18, 2007Assignee: International Business Machines CorporationInventor: Stuart Stephen Papworth Parkin
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Patent number: 7271986Abstract: A magnetoresistive sensor having two free layers with shape anisotropy induced magnetic alignment is disclosed. The magnetoresistive sensor includes a first ferromagnetic free layer having a first quiescent state magnetization direction. The magnetoresistive sensor also includes a second elongated free layer having a second quiescent state magnetization direction and positioned such that the first quiescent state magnetization direction is generally orthogonal to the second quiescent state magnetization direction. Further, a portion of the second ferromagnetic free layer overlaps a portion of the first ferromagnetic free layer proximal to an air bearing surface to form a v-shape. A nonmagnetic spacer layer is also positioned between the first ferromagnetic free layer and the second ferromagnetic free layer.Type: GrantFiled: November 26, 2002Date of Patent: September 18, 2007Assignee: Seagate Technology LLCInventors: Victor B. Sapozhnikov, Taras G. Pokhil, Olle G. Heinonen, Janusz J. Nowak
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Patent number: 7268985Abstract: A magnetic head having an improved read head structure. The read head includes a free magnetic layer with hard bias elements disposed proximate its ends, where the hard bias elements include an improved hard bias magnetic grain structure. This is accomplished by fabricating the hard bias element as a bilayer structure having a first hard bias sublayer, a nonmagnetic midlayer and a second hard bias sublayer. The midlayer is preferably composed of a nonmagnetic material such as chromium, and the hard bias sublayers are composed of a magnetic material such as CoPtCr. Each sublayer is formed with its own magnetic grains, and because there are two sublayers, the hard bias element is fabricated with approximately twice the number of magnetic grains as the prior art single layer hard bias element.Type: GrantFiled: May 28, 2004Date of Patent: September 11, 2007Assignee: Hitachi Global Storage Technologies Netherlands, B.V.Inventors: James Mac Freitag, James L. Nix, Mustafa Michael Pinarbasi
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Patent number: 7268981Abstract: In one illustrative example, a spin valve sensor includes a free layer structure; an anti-parallel (AP) pinned layer structure which includes at least a first AP pinned layer; and a non-magnetic electrically conductive spacer layer formed between the free layer structure and the AP pinned layer structure. First and second antiferromagnetic (AFM) pinning layer structures for magnetically pinning the first AP pinned layer are formed in end regions but are absent from its central region. Edges of each AFM pinning layer structure may be separated by a distance DA from the sensor edges. The first AP pinned layer is formed in both the central region and the end regions so as to be in contact with the first and second AFM pinning layer structures. Advantageously, adequate pinning properties are exhibited in a sensor which provides the benefits of a self-pinned sensor (e.g. a reduced sensor profile in the central region).Type: GrantFiled: April 30, 2004Date of Patent: September 11, 2007Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventor: David Eugene Heim
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Patent number: 7265947Abstract: The series resistance of a CPP read head having in-stack biasing has been reduced by stitching the AFM layer through a high conductance layer. Both the AFM and high conductance layers have significantly larger cross-sectional areas than the high conductance layer of prior art structures so the contribution, to the total resistance of the device, from the AFM layer as well as from spreading resistance at the stack-lead interface, is significantly reduced. The high conductance layer provides sufficient ferromagnetic coupling to enable the AFM to stabilize the in-stack bias layer. A process to manufacture the device is also described.Type: GrantFiled: November 3, 2004Date of Patent: September 4, 2007Assignee: Headway Technologies, Inc.Inventors: Youfeng Zheng, Kochan Ju
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Patent number: 7265949Abstract: A magneto-resistance effect element is adapted that a non-magnetic layer (9, 18), a free layer (3b, 19), another non-magnetic layer (4, 25), a fixed layer (5, 26), and a fixing layer (6b, 27) are formed vertically symmetric with respect to a first magnetic layer (8b), to which a vertical bias magnetic field is applied from an underlying layer (2a) for a vertical bias layer (2b). The magneto-resistance effect element operates in CPP mode. Generally, the free layer is unavoidably subjected to the influence of a circular electric magnetic field caused by a current flowing perpendicularly to the film surface. However, in the magneto-resistance effect element, the influence of the electric magnetic field to which the free layer (3b) is subjected is opposite to that of the electric magnetic field to which the second free layer (19) is subjected, thereby canceling out the influences as a hole.Type: GrantFiled: June 30, 2006Date of Patent: September 4, 2007Assignee: NEC CorporationInventors: Kazuhiko Hayashi, Junichi Fujikata, Tsutomu Ishi, Shigeru Mori, Keishi Ohashi, Masafumi Nakada, Kiyokazu Nagahara, Kunihiko Ishihara, Nobuyuki Ishiwata
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Patent number: 7265948Abstract: No related magnetoresistive multi-layered films made from a metal magnetic film provide sufficient reproducing output power. A high-polarized layer with a thickness of 10 nm or less is formed as a Fe-rich Fe—O layer in contact with the interface of a non-magnetic intermediate layer and the resulting layers are heat treated to form a multi-layered film of ferromagnetic Fe—O layers, achieving a magnetoresistive element having high magnetoresistance.Type: GrantFiled: November 7, 2005Date of Patent: September 4, 2007Assignee: Hitachi Global Storage Technologies Japan, Ltd.,Inventors: Hiroyuki Hoshiya, Susumu Soeya, Kenichi Meguro
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Patent number: 7262941Abstract: 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. As a result of their structure and the method of their fabrication, these elements have higher GMR ratios and lower resistances than elements of the prior art.Type: GrantFiled: May 28, 2004Date of Patent: August 28, 2007Assignee: Headway Technologies, Inc.Inventors: Min Li, Simon H. Liao, Masashi Sano, Kiyoshi Noguchi, Kochan Ju, Cheng T. Horng
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Publication number: 20070195469Abstract: A magnetoresistive effect element includes: a magnetoresistive effect film including a magnetization free layer, a magnetization fixed layer, and an intermediate layer placed between them; a magnetic coupling layer; a ferromagnetic layer; an antiferromagnetic layer; a bias mechanism portion applying a bias magnetic field to the magnetization free layer in a direction nearly parallel to a film surface of the magentoresistive effect film and nearly perpendicular to a magnetization direction of the magnetization fixed layer; and a pair of electrodes to pass a current in a direction going from the magnetization fixed layer to the magnetization free layer, and its bias point is more than 50%.Type: ApplicationFiled: November 13, 2006Publication date: August 23, 2007Applicant: Kabushiki Kaisha ToshibaInventors: Masahiro Takashita, Masayuki Takagishi, Hitoshi Iwasaki, Shiho Nakamura
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Patent number: 7259940Abstract: A pair of domain control layers are disposed on both sides of the track width direction of the MR film so as to be separated from each other such that the MR film is held therebetween, and apply a longitudinal magnetic field to the MR film (free layer). The MR film is flanked by the domain control layers, each including a layer structure constituted by a base layer, a ferromagnetic layer, and a hard magnetic layer. The base layer causes the hard magnetic layer to have a magnetization direction aligning with an in-plane direction, so as to enhance the coercive force of the hard magnetic layer.Type: GrantFiled: July 13, 2004Date of Patent: August 21, 2007Assignee: TDK CorporationInventors: Kosuke Tanaka, Koji Shimazawa, Koichi Terunuma, Tomoaki Shimizu
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Patent number: 7259941Abstract: A magnetoresistive sensor having a hard bias structure having increased coercivity and squareness. The structure also allows the use of a thinner seed layer, which results in improved biasing by decreasing the spacing between the hard magnetic bias layer and the free layer of the sensor. The hard bias structure can be deposited over either a crystalline structure or over an amorphous material. The hard bias structure includes a hard bias material comprising CoPt deposited over a seed layer including a layer of NiTa and a layer of CrMo.Type: GrantFiled: October 27, 2004Date of Patent: August 21, 2007Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventor: Mustafa Michael Pinarbasi
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Patent number: 7259942Abstract: In one illustrative example, a three terminal magnetic sensor (TTM) suitable for use in a magnetic head has a base region, a collector region, and an emitter region. A first barrier layer is located between the emitter region and the base region, and a second barrier layer is located between the collector region and the base region. A sensing plane is defined along sides of the base region, the collector region, and the emitter region. The base region has a free layer structure, a pinned layer structure adjacent the first barrier layer, and a non-magnetic spacer layer located between the free layer structure and the pinned layer structure. The collector region comprises an in-stack longitudinal biasing layer (LBL) structure which magnetically biases the free layer structure, where the second barrier layer serves as a non-magnetic spacer layer for the in-stacking biasing layer structure. In one variation, the layers are inverted such that the emitter region has the in-stack LBL structure.Type: GrantFiled: January 10, 2005Date of Patent: August 21, 2007Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Jeffrey R. Childress, Jeffrey S. Lille
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Publication number: 20070188945Abstract: A magnetoresistive effect element includes a fixed magnetization layer; a free magnetization layer; a nonmagnetic spacer layer between the fixed magnetization layer and the free magnetization layer; and an insertion layer disposed on an opposite side of the free magnetization layer from the nonmagnetic spacer layer, wherein the first insulating layer has an oxide, a nitride, or an oxynitride including at least one kind of element selected from a group constituted of Al(aluminum), Si(silicon), Mg(magnesium), Ta(tantalum) and Zn(zinc) as a major constituent, and the insertion layer has an oxide, a nitride, or an oxynitride including at least one kind of element selected from a group constituted of Al(aluminum), Si(silicon), Mg(magnesium), Ta(tantalum) and Zn(zinc) as a major constituent.Type: ApplicationFiled: February 6, 2007Publication date: August 16, 2007Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Yoshihiko Fuji, Hideaki Fukuzawa, Hiromi Yuasa, Hitoshi Iwasaki
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Publication number: 20070188946Abstract: A current sensor capable of detecting current magnetic fields generated by a current to be detected with high precision and stability while realizing a compact configuration is provided. The current sensor includes: a conductor generating a current magnetic field in accordance with supplied current to be detected; a magnetoresistive element including a free layer having a magnetization direction that varies in accordance with the current magnetic field, a pinned layer having the magnetization direction that is pinned to a direction orthogonal to the magnetization direction of the free layer under no current magnetic field, and an intermediate layer provided between the free layer and the pinned layer; and a bias applying means for applying, to the magnetoresistive element, a bias magnetic field along a direction same with the magnetization direction of the free layer under no current magnetic field.Type: ApplicationFiled: February 13, 2007Publication date: August 16, 2007Applicant: TDK CORPORATIONInventor: Shigeru Shoji
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Patent number: 7256971Abstract: A CPP-GMR spin value sensor structure with an improved MR ratio and increased resistance is disclosed. All layers except certain pinned layers, copper spacers, and a Ta capping layer are oxygen doped by adding a partial O2 pressure to the Ar sputtering gas during deposition. Oxygen doped CoFe free and pinned layers are made slightly thicker to offset a small decrease in magnetic moment caused by the oxygen dopant. Incorporating oxygen in the MnPt AFM layer enhances the exchange bias strength. An insertion layer such as a nano-oxide layer is included in one or more of the free, pinned, and spacer layers to increase interfacial scattering. The thickness of all layers except the copper spacer may be increased to enhance bulk scattering. A CPP-GMR single or dual spin valve of the present invention has up to a threefold increase in resistance and a 2 to 3% increase in MR ratio.Type: GrantFiled: March 9, 2004Date of Patent: August 14, 2007Assignee: Headway Technologies, Inc.Inventors: Cheng T. Horng, Ru-Ying Tong
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Patent number: 7256972Abstract: A current perpendicular to plane (CPP) sensor having an in stack bias layer having a desired negative magnetostriction for efficient biasing of the free layer. The sensor includes a free layer, a pinned layer and a first spacer layer sandwiched between the free layer and the pinned layer. The sensor further includes an in stack bias structure disposed adjacent to the free layer, opposite the first spacer layer. The in stack bias structure includes a layer of CoFe exchange coupled with a layer of antiferomagnetic (AFM) material. A layer of CoX is then exchange coupled to the layer of CoFe. The element X can be selected from the material including B, Si, SiB, Ni, Nb, and Y.Type: GrantFiled: June 30, 2004Date of Patent: August 14, 2007Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventor: Hardayal Singh Gill
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Patent number: 7252852Abstract: ZnMg oxide tunnel barriers are grown which, when sandwiched between ferri- or ferromagnetic layers, form magnetic tunnel junctions exhibiting high tunneling magnetoresistance (TMR). The TMR may be increased by annealing the magnetic tunnel junctions. The zinc-magnesium oxide tunnel barriers may be incorporated into a variety of other devices, such as magnetic tunneling transistors and spin injector devices. The ZnMg oxide tunnel barriers are grown by first depositing a zinc and/or magnesium layer onto an underlying substrate in oxygen-poor (or oxygen-free) conditions, and subsequently depositing zinc and/or magnesium onto this layer in the presence of reactive oxygen.Type: GrantFiled: November 5, 2004Date of Patent: August 7, 2007Assignee: International Business Machines CorporationInventor: Stuart Stephen Papworth Parkin
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Patent number: 7248448Abstract: Disclosed are a high-sensitivity and high-reliability magnetoresistance effect device (MR device) in which bias point designing is easy, and also a magnetic head, a magnetic head assembly and a magnetic recording/reproducing system incorporating the MR device. In the MR device incorporating a spin valve film, the magnetization direction of the free layer is at a certain angle to the magnetization direction of a second ferromagnetic layer therein when the applied magnetic field is zero. In this, the pinned magnetic layer comprises a pair of ferromagnetic films as antiferromagnetically coupled to each other via a coupling film existing therebetween.Type: GrantFiled: September 10, 2004Date of Patent: July 24, 2007Assignee: Kabushiki Kaisha ToshibaInventors: Hideaki Fukuzawa, Yuzo Kamiguchi, Katsuhiko Koui, Shin-ichi Nakamura, Hitoshi Iwasaki, Kazuhiro Saito, Hiromi Fuke, Masatoshi Yoshikawa, Susumu Hashimoto, Masashi Sahashi
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Patent number: 7248445Abstract: A magnetic sensing element includes a composite film, a lower shield layer, and a lower electrode layer and an upper electrode layer for supplying a current perpendicular to the composite film. The composite film has an antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic layer, and a free magnetic layer. The composite film has a top face and two side faces in a track width direction. Each of the two side faces has a bent position. The angle defined by the side face below the bent position and the top face is larger than the angle defined by the side face above the bent position and the top face. The bent portion preferably lies on the lower electrode layer or the lower shield layer.Type: GrantFiled: September 11, 2002Date of Patent: July 24, 2007Assignee: Alps Electric Co., Ltd.Inventor: Yoshihiro Nishiyama
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Patent number: 7243412Abstract: A method of manufacturing a magnetic head including a magnetic sensing portion formed of a magnetoresistive effect element, a magnetoresistive effect magnetic head manufacturing method depositing, via a film deposition process, a lamination layer having a free layer comprised of a soft magnetic material of which the magnetization is rotated in response to an external magnetic field, a fixed layer comprised of a ferromagnetic material, an antiferromagnetic layer for fixing the magnetization of said fixed layer, a magnetic flux introducing layer with a tip end of which is opposed to a surface which is brought in contact with or opposed to a magnetic recording medium, and a spacer layer interposed between said free layer and said fixed layer; patterning at least said free layer and said fixed layer with a mask such that opposing side surfaces of said free layer and said fixed layer are formed of one continuous surface; and forming hard magnetic layers having high or low resistance for maintaining a magnetic stabType: GrantFiled: August 14, 2002Date of Patent: July 17, 2007Assignee: Sony CorporationInventors: Akio Furukawa, Yoshihiko Kakihara
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Patent number: 7245463Abstract: A Giant Magneto-Resistive (GMR) sensor (900) having Current Perpendicular to Plane (CPP) structure provides an extended first pinned layer (914) as compared to second pinned layer (912) and free layer (910). Increased magnetoresistance changes, increased pinning strength, increased thermal stability, and decreased susceptibility to Electro-Static Discharge (ESD) events is realized by maintaining equivalent current densities through free layer (910) and second pinned layer (912), while decreasing the relative current density through first pinned layer (914).Type: GrantFiled: July 25, 2003Date of Patent: July 17, 2007Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventor: Hardayal Singh Gill
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Patent number: 7242556Abstract: A current perpendicular to plane (CPP) differential giant magnetoresistive (GMR) sensor that is insensitive to stray longitudinal and transverse magnetic fields. The sensor includes an in stack bias layer structure that is used to bias the magnetic moment of first and second free layers disposed at either side thereof. The bias structure includes an antiferromagnetic layer (AFM). An odd number of antiparallel (AP) coupled magnetic layers are formed on a first side of the AFM and an even number of AP coupled magnetic layers on the opposite side of the AFM.Type: GrantFiled: June 21, 2004Date of Patent: July 10, 2007Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventor: Hardayal Singh Gill
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Patent number: 7237322Abstract: A method for making a tunnel valve head with a flux guide. The tunnel valve sensor is created by forming a tunnel valve at a first shield layer. The tunnel valve includes a free layer distal to the first shield layer, a first insulation layer deposited over the first shield layer and around the tunnel valve, a flux guide formed over the first insulation layer and coupling to the tunnel valve at the free layer, a second insulation layer formed over the flux guide and a second shield layer formed over the second insulation layer. The flux guide and the free layer are physically isolated by the first and second insulation layers to prevent current shunts therefrom. The structure achieves physical connection between the flux guide and the free layer and insulates the flux guide from the shields.Type: GrantFiled: October 29, 2004Date of Patent: July 3, 2007Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventor: Hardayal Singh Gill
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Patent number: 7234228Abstract: A method for forming a bottom spin valve sensor element with a novel seed layer and synthetic antiferromagnetic pinned layer. The novel seed layer comprises an approximately 30 angstrom thick layer of NiCr whose atomic percent of Cr is 31%. On this seed layer there can be formed either a single bottom spin valve read sensor or a symmetric dual spin valve read sensor having synthetic antiferromagnetic pinned layers. An extremely thin (approximately 80 angstroms) MnPt pinning layer can be formed directly on the seed layer and extremely thin pinned and free layers can then subsequently be formed so that the sensors can be used to read recorded media with densities exceeding 60 Gb/in2. Moreover, the high pinning field and optimum magnetostriction produces an extremely robust sensor.Type: GrantFiled: December 3, 2002Date of Patent: June 26, 2007Assignee: Headway Technologies, Inc.Inventors: Cheng T. Horng, Hui-Chuan Wang, Ru-Ying Tong, Chyu-Jiuh Trong
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Patent number: 7236336Abstract: A method and apparatus for providing a free layer having higher saturation field capability and optimum sensitivity (dr/R) is disclosed. The present invention provides a synthetic free layer that includes a first and second free layer, wherein the second free layer is a cobalt alloy that provides higher saturation and optimum sensitivity.Type: GrantFiled: April 30, 2004Date of Patent: June 26, 2007Assignee: Hitachi Global Storage Technologies Inc, Netherlands B.V.Inventor: Hardayal Singh Gill
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Patent number: 7233461Abstract: A magnetic head has a read sensor which includes at least one primary pinned layer, a barrier layer, and a free layer. An in-stack biasing structure having net magnetic moment near zero, notated as dM=0, is constructed above the free layer. This in-stack biasing structure acts to stabilize the free layer by exchange coupling.Type: GrantFiled: January 20, 2004Date of Patent: June 19, 2007Assignee: Hitachi Global Storage Technologies Netherlands, B.V.Inventor: Hardayal Singh Gill
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Patent number: 7230845Abstract: A method and system for providing a magnetic memory device are disclosed. The method and system include providing a magnetic element that includes a data storage layer having at least one easy axis in at least a first direction. The method and system also include providing a hard bias structure surrounding a portion of the magnetic element. The hard bias structure is also configured to provide at least one hard bias field essentially parallel to the at least the first direction or essentially perpendicular to the at least the first direction.Type: GrantFiled: July 29, 2005Date of Patent: June 12, 2007Assignee: Grandis, Inc.Inventors: Lien-Chang Wang, Yiming Huai
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Patent number: 7228617Abstract: The GMR read head includes a GMR read sensor and a longitudinal bias (LB) stack in a read region, and the GMR read sensor, the LB stack and a first conductor layer in two overlay regions. In its fabrication process, the GMR read sensor, the LB stack and the first conductor layer are sequentially deposited on a bottom gap layer. A monolayer photoresist is deposited, exposed and developed in order to open a read trench region for the definition of a read width, and RIE is then applied to remove the first conductor layer in the read trench region. After liftoff of the monolayer photoresist, bilayer photoresists are deposited, exposed and developed in order to mask the read and overlay regions, and a second conductor layer is deposited in two unmasked side regions. As a result, side reading is eliminated and a read width is sharply defined by RIE.Type: GrantFiled: September 29, 2003Date of Patent: June 12, 2007Assignee: Hitachi Global Storage Technologies Netherlands, B.V.Inventors: Tsann Lin, Daniele Mauri
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Patent number: 7230803Abstract: A magneto-resistive effect head including: an antiferromagnetic layer; a pinned layer which is formed on the antiferromagnetic layer and whose magnetizing direction has been fixed; a spacer formed on the pinned layer; a free layer formed on the spacer; and magnetic domain control layers having antiferromagnetic flims and magnet layers for performing a magnetic domain control of the free layer; wherein the each of the antiferromagnetjc films is formed on the free layer; wherein the each of magnet layers has at least two magnetic films coupled anti-ferromagnetically through at least one nonmagnetic film; a pair of lead layers for supplying a current to the stack of layers; and wherein seed layers are formed between the antiferromagnetic films and the lead layers.Type: GrantFiled: February 5, 2004Date of Patent: June 12, 2007Assignee: Hitachi, Ltd.Inventors: Akira Morinaga, Koichi Nishioka, Takayoshi Ohtsu, Norifumi Miyamoto, Shuichi Kojima
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Patent number: 7230802Abstract: A method and apparatus for providing magnetostriction control in a free layer of a magnetic memory device is disclosed. The same target compositions for the free layers may be used, but the relative thickness values are modified to obtain a desired magnetostriction without a change in the magenetoristance ratio, ?R/R.Type: GrantFiled: November 12, 2003Date of Patent: June 12, 2007Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: James Mac Freitag, Mustafa Michael Pinarbasi
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Patent number: 7229706Abstract: The present invention provides a magnetic detecting element capable of increasing a difference between the ease of a conduction electron flow in a low-resistance state and the ease of a conduction electron flow in a high-resistance state to increase a resistance change ?R. In the magnetic detecting element, a free magnetic layer or a pinned magnetic layer has a synthetic ferromagnetic structure including a first free magnetic sub-layer or a first pinned magnetic sub-layer containing a magnetic material having a positive ? value, and a second magnetic sub-layer or a second pinned magnetic sub-layer containing a magnetic material having a negative ? value. The ? value is characteristics of a magnetic material satisfying the relationship ??/??=(1+?)/(1??)(?1???1)(wherein ?? represents resistivity for minority conduction electrons, and ?? represents resistivity for majority conduction electrons).Type: GrantFiled: January 12, 2004Date of Patent: June 12, 2007Assignee: Alps Electric Co., Ltd.Inventors: Naoya Hasegawa, Masamichi Saito
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Patent number: 7230801Abstract: The GMR read head includes a GMR read sensor and a longitudinal bias (LB) stack in a read region, and the GMR read sensor, the LB stack and a first conductor layer in two overlay regions. In its fabrication process, the GMR read sensor, the LB stack and the first conductor layer are sequentially deposited on a bottom gap layer. A monolayer photoresist is deposited, exposed and developed in order to open a read trench region for the definition of a read width, and RIE is then applied to remove the first conductor layer in the read trench region. After liftoff of the monolayer photoresist, bilayer photoresists are deposited, exposed and developed in order to mask the read and overlay regions, and a second conductor layer is deposited in two unmasked side regions. As a result, side reading is eliminated and a read width is sharply defined by RIE.Type: GrantFiled: August 24, 2004Date of Patent: June 12, 2007Assignee: Hitachi Global Storage Technologies Netherlands, B.V.Inventors: Tsann Lin, Daniele Mauri
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Patent number: 7223485Abstract: A magnetoresistive device includes a magnetization pinned layer, a magnetization free layer, a nonmagnetic intermediate layer formed between the magnetization pinned layer and the magnetization free layer, and electrodes allowing a sense current to flow in a direction substantially perpendicular to the plane of the stack including the magnetization pinned layer, the nonmagnetic intermediate layer and the magnetization free layer. At least one of the magnetization pinned layer and the magnetization free layer is substantially formed of a binary or ternary alloy represented by the formula FeaCobNic (where a+b+c=100 at %, and a?75 at %, b?75 at %, and c?63 at %), or formed of an alloy having a body-centered cubic crystal structure.Type: GrantFiled: March 7, 2005Date of Patent: May 29, 2007Assignee: Kabushiki Kaisha ToshibaInventors: Hiromi Yuasa, Masatoshi Yoshikawa, Yuzo Kamiguchi, Hitoshi Iwasaki, Masashi Sahashi