Treating To Affect Magnetic Properties Patents (Class 29/603.08)
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Publication number: 20040223269Abstract: 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.Type: ApplicationFiled: May 28, 2004Publication date: November 11, 2004Applicant: HEADWAY TECHNOLOGIES, INC.Inventors: Po Kang Wang, Moris Dovek, Jibin Geng, Tai Min
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Patent number: 6813824Abstract: A liquid resist is introduced between adjacent conductive lines of a coil pattern girdling around a magnetic core piece. When the liquid resist is cured, an insulating resin filler can be fixed between the adjacent conductive lines of the coil pattern. An insulating metallic layer is formed to extend over the insulting resin filler and the conductive lines of the coil pattern. Thereafter, the insulating metallic layer is subjected to a flattening grinding treatment until at least a part of the conductive line is exposed at a flattened surface. Of the resist, of a higher fluidity, penetrates in every hole and corner between the adjacent conductive lines, the gap defined between the adjacent conductive lines is fully filled with the insulating material. No voids remain in the gap. The conductive line of the coil can be reliably prevented from corrosion or oxidation. Moreover, a relatively brittle of fragile insulating resin filler is reliably prevented from being subjected to the flattening.Type: GrantFiled: December 23, 2002Date of Patent: November 9, 2004Assignee: Fujitsu LimitedInventors: Minoru Hasegawa, Yoshinori Ohtsuka, Yuji Uehara, Takashi Sekikawa, Hiroshi Maeda, Masahiro Kakehi, Ikuya Tagawa, Tomoko Kutsuzawa, Syuji Nishida
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Publication number: 20040194292Abstract: A method of manufacturing a magnetic tunnel junction device, in which a stack (1) comprising two electrode layers (3, 7) and a barrier layer (5) extending in between is formed. One of the electrode layers is structured by means of etching, in which, during etching, a part of this layer is made thinner by removing material until a rest layer (7r) remains. This rest layer is subsequently removed by means of physical etching, in which at least substantially charged particles have a motion energy which is between the sputtering threshold of the magnetic material of the rest layer and the sputtering threshold of the non-magnetic material of the barrier layer. In the relevant method, it is prevented that the electrode layer which is not to be structured is detrimentally influenced during structuring of the other electrode layer.Type: ApplicationFiled: April 20, 2004Publication date: October 7, 2004Inventor: Joannes Baptist Adrianus Dionisius Van Zon
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Publication number: 20040182479Abstract: 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: ApplicationFiled: March 21, 2003Publication date: September 23, 2004Applicant: Headway Technologies, Inc.Inventors: Yimin Guo, Li-Yan Zhu
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Patent number: 6785954Abstract: 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.Type: GrantFiled: April 17, 2002Date of Patent: September 7, 2004Assignee: Headway Technologies, Inc.Inventors: Cheng T. Horng, Mao-Min Chen, Chen-Jung Chien, Cherng-Chyi Han, Ru-Ying Tong, Chyu-Jiuh Torng, Hui-Chuan Wang
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Patent number: 6788500Abstract: A system, method and computer program product provide an annealing process for setting a magnetization condition of a read head. An amount of heat for stabilizing magnetization condition of a read head is calculated. A width and amplitude of a voltage pulse that generates the calculated amount of heat in the read head are calculated. A voltage pulse of the calculated width and amplitude is applied to the read head for generating Joule heating in the read head. The width of the voltage pulse is less than one second.Type: GrantFiled: May 6, 2002Date of Patent: September 7, 2004Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Lydia Baril, Ciaran A. Fox, Jih-Shiuan Luo, Peter J. Melz, Chin-Yu Yeh
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Publication number: 20040165321Abstract: A magnetic sensor includes a pinned magnetic layer having first and second magnetic sublayers sandwiching a nonmagnetic metal layer. The nonmagnetic metal layer contains at least one of Ru, Re, Os, Ti, Rh, Ir, Pd, Pt, and Al. The atoms in the first magnetic sublayer and the atoms in the nonmagnetic metal layer overlap with each other, while each of the crystal structures is deformed. The deformations in the crystal structure of the first magnetic sublayer increase the magnetostriction constant, thereby increasing the magnetoelastic effect of the magnetic sensor.Type: ApplicationFiled: February 20, 2004Publication date: August 26, 2004Applicant: Alps Electric Co., Ltd.Inventors: Naoya Hasegawa, Eiji Umetsu, Masamichi Saito, Yosuke Ide
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Publication number: 20040165317Abstract: 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.Type: ApplicationFiled: February 26, 2004Publication date: August 26, 2004Inventor: John David Westwood
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Patent number: 6780338Abstract: The subject invention pertains instruments for use in nuclear spin tomography comprising a metal alloy comprising aluminum, vanadium, and titanium. In a specific embodiment, the subject invention relates to cardiovascular stents which can exhibit a low incidence of artifacts and are viewable in a nuclear spin tomography unit. The subject invention also pertains to a method for processing instruments for use in nuclear spin tomography. Such processing can comprise application of a wet chemical etching solution. In a specific embodiment, the wet chemical etching solution can comprise three parts hydrochloric acid and two parts saltpeter acid.Type: GrantFiled: March 5, 2002Date of Patent: August 24, 2004Assignee: MRI Devices Daum GmbHInventors: Wolfgang Daum, Axel Winkel
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Patent number: 6779248Abstract: 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.Type: GrantFiled: March 7, 2002Date of Patent: August 24, 2004Assignee: Headway Technologies, Inc.Inventors: Moris M. Dovek, Tai Min
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Patent number: 6775903Abstract: A method for forming top and bottom spin valve sensors and the sensors so formed, the sensors having a strongly coupled SyAP pinned layer and an ultra-thin antiferromagnetic pinning layer. The two strongly coupled ferromagnetic layers comprising the SyAP pinned layer in the top valve configuration are separated by a Ru spacer layer approximately 3 angstroms thick, while the two layers in the bottom spin valve configuration are separated by a Rh spacer layer approximately 5 angstroms thick. This allows the use of an ultra thin MnPt antiferromagnetic pinning layer of thickness between approximately 80 and approximately 150 angstroms. The sensor structure produced thereby is suitable for high density applications.Type: GrantFiled: September 17, 2001Date of Patent: August 17, 2004Assignee: Headway TechnologInventors: Cheng T. Horng, Kochan Ju, Mao-Min Chen, Min Li, Ru-Ying Tong, Simon Liao
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Publication number: 20040154159Abstract: A thin-film magnetic head comprises a reproducing head and a recording head. The reproducing head comprises: a GMR element; a bottom shield layer and a top shield layer for shielding the GMR element; conductive layers connected to the GMR element; and shield gap films formed between the shield layers. Each of the shield gap films is made up of a plurality of thin alumina films stacked that are formed by performing the step of forming a thin alumina film by low pressure CVD, for example, a plurality of times.Type: ApplicationFiled: March 2, 2004Publication date: August 12, 2004Applicant: TDK CorporationInventors: Yoshitaka Sasaki, Tohru Inoue
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Patent number: 6773515Abstract: 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.Type: GrantFiled: January 16, 2002Date of Patent: August 10, 2004Assignee: Headway Technologies, Inc.Inventors: Min Li, Simon H. Liao, Masashi Sano, Kiyoshi Noguchi, Kochan Ju, Cheng T. Horng
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Patent number: 6772507Abstract: A method of manufacturing a magnetic recording medium having a disc-shaped flexible slave medium accommodated in a case, onto which servo signals are effectively recorded by a magnetic transfer method with high quality. The method includes a slitting step for cutting an original sheet into discrete webs; a punching step for obtaining a disc-shaped slave medium; a thermo step for removing distortion; a burnishing step for smoothing a surface of the slave medium; a center core attachment step; a magnetic transfer step for performing a magnetic transfer while a master medium is allowed to be brought into close contact with one of the web and the slave medium; an assembly step for incorporating slave medium into the case; a cleaning step for cleaning a surface of the slave medium; a verifying step for checking the servo signals; and a packing step.Type: GrantFiled: September 12, 2001Date of Patent: August 10, 2004Assignee: Fuji Photo Film Co., Ltd.Inventor: Masashi Aoki
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Patent number: 6769170Abstract: A method of manufacturing a ferromagnetic tunnel junction element, having an insulating film, a first ferromagnetic film and a second ferromagnetic film, including a step of turning the ferromagnetic tunnel junction element on electricity for a given period before a practical operation of the ferromagnetic tunnel junction element, so that a resistance of the insulating film is stabilized.Type: GrantFiled: July 7, 2000Date of Patent: August 3, 2004Assignee: TDK CorporationInventors: Koji Shimazawa, Satoru Araki
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Patent number: 6757962Abstract: In a method for manufacturing a magnetic field sensing element including an electrode layer overlying a second antiferrogmagnetic layer and a first free magnetic layer where the electrode layer exposes a portion of the second magnetic layer, a portion of the second antiferromagnetic layer not covered with the electrode layer and a portion of the first free magnetic layer are removed using the electrode layer as a mask after laminating each layer to form a bottom type spin-valve thin film magnetic element, thereby enabling the first free magnetic layer to be endowed with a sufficient exchange coupling magnetic field by substantially eliminating the tapered portion of the remaining second antiferromagnetic layer thereby enabling the magnetization of the second free magnetic layer to be put into a single domain state.Type: GrantFiled: December 10, 2001Date of Patent: July 6, 2004Assignee: Alps Electric Co., Ltd.Inventors: Naoya Hasegawa, Eiji Umetsu, Masamichi Saito, Kenichi Tanaka, Yosuke Ide
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Publication number: 20040095691Abstract: An antiferromagnetic stabilization scheme is employed in a magnetic head for magnetically stabilizing a free layer of a spin valve. This is accomplished by utilizing an antiferromagnetic oxide film below a spin valve sensor in a read region and first and second lead layers in end regions and a ferromagnetic film in each of the lead layers that exchange couples to the antiferromagnetic oxide film in the end regions. The ferromagnetic films are pinned with their magnetic moments oriented parallel to an air bearing surface (ABS) of the magnetic head. The ferromagnetic film magnetostatically couples to the free layer which causes the free layer to be in a single magnetic domain state. Accordingly, when the free layer is subjected to magnetic incursions from a rotating disk in a disk drive, the free layer maintains a stable magnetic condition so that resistance changes of the free layer are not altered by differing magnetic conditions of the free layer.Type: ApplicationFiled: November 7, 2003Publication date: May 20, 2004Inventors: Tsann Lin, Daniele Mauri
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Publication number: 20040095690Abstract: 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.Type: ApplicationFiled: October 24, 2003Publication date: May 20, 2004Inventor: Robert S. Beach
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Publication number: 20040080874Abstract: The invention provides a magnetoresistive element in which the pinned magnetic layer includes at least one non-magnetic film and magnetic films sandwiching that non-magneticfilm, and the magnetic films are coupled with one another by magnetostatic coupling via the non-magnetic film. This element has an improved thermal resistance. Furthermore, the invention provides a magnetoresistive element in which the pinned magnetic layer is as described above. The magnetic films can be coupled with one another by magnetostatic coupling or antiferromagnetic coupling generating negative magnetic coupling. In this element, the magnetic field shift is reduced. Furthermore, the invention provides a magnetoresistive element in which at least one of the magnetic layers sandwiching the intermediate layer includes an oxide ferrite having a plane orientation with a (100), (110) or (111) plane. A magnetic field is introduced in a direction of the axis of easy magnetization in the plane.Type: ApplicationFiled: October 16, 2003Publication date: April 29, 2004Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.Inventors: Masayoshi Hiramoto, Hiroshi Sakakima, Hideaki Adachi, Nozomu Matukawa, Kenji Iijima, Mitsuo Satomi
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Publication number: 20040078959Abstract: A method of adjusting or locally modifying the direction of magnetization of a ferromagnetic layer in a magnetoresistive layer system using a heat stamp is described, the ferromagnetic layer being stabilized over an antiferromagnetic layer. The antiferromagnetic layer is heated, using a heat stamp, over a threshold temperature, above which the influence of this layer on the direction of magnetization of the adjacent ferromagnetic layer disappears; subsequently, the ferromagnetic layer is exposed to an external magnetic field of a predefined direction, and finally the antiferromagnetic layer is cooled again below the threshold temperature. In addition, a heat stamp having a base body and a heatable stamp structure connected to the base body and matching the dimensions of or similar to the magnetoresistive layer system is described.Type: ApplicationFiled: July 7, 2003Publication date: April 29, 2004Inventors: Henrik Siegle, Andrew Johnson, Ulrich May
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Publication number: 20040080872Abstract: A magnetic sensor comprises magnetoresistive elements and permanent magnet films, which are combined together to form GMR elements formed on a quartz substrate having a square shape, wherein the permanent magnet films are paired and connected to both ends of the magnetoresistive elements, so that an X-axis magnetic sensor and a Y-axis magnetic sensor are realized by adequately arranging the GMR elements relative to the four sides of the quartz substrate. Herein, the magnetization direction of the pinned layer of the magnetoresistive element forms a prescribed angle of 45° relative to the longitudinal direction of the magnetoresistive element or relative to the magnetization direction of the permanent magnet film. Thus, it is possible to reliably suppress offset variations of bridge connections of the GMR elements even when an intense magnetic field is applied; and it is therefore possible to noticeably improve the resistant characteristics to an intense magnetic field.Type: ApplicationFiled: October 16, 2003Publication date: April 29, 2004Inventors: Hideki Sato, Kokichi Aiso, Yukio Wakui
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Publication number: 20040075958Abstract: A magnetoresistive (MR) device includes a synthetic antiferromagnetic (AFM) layer having an Fe/FeSi/Fe construction. A first Fe layer of the synthetic AFM layer has a magnetization substantially in a first direction, while a second Fe layer of the synthetic AFM layer has a magnetization substantially in a second direction that is substantially antiparallel to the first direction. The magnetoresistive device can be a spin valve in which a first surface of the synthetic AFM layer is adjacent to a pinning layer, and a second surface of the synthetic AFM layer is adjacent to a spacer layer. Further, the spin valve includes a free layer that overlies the spacer, thereby being separated from the synthetic AFM layer by the spacer. The pinning layer, synthetic AFM layer, spacer, and free layer can be bounded by a first shield and a second shield to provide magnetic shielding of the spin valve sensor.Type: ApplicationFiled: October 14, 2003Publication date: April 22, 2004Applicant: Western Digital (Fremont)Inventors: Chih-Huang Lai, Zhupei Shi, Hua-Ching Tong, Robert E. Rottmayer, Charles W. Miller
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Patent number: 6718621Abstract: In a production process of an MR head using the tunnel junction film basically consisting of a free layer, a barrier layer, and a pinned layer, the resistance between the free layer and the pined layer reduced beforehand and increased afterward up to a resistance value necessary when actually used. While the resistance between the free layer and the pinned layer is low, current can easily flow, suppressing charge up, thus preventing insulation destruction of the barrier layer. This significantly increases a production yield of a recording/reproduction head using a ferromagnetic tunnel junction element.Type: GrantFiled: May 9, 2000Date of Patent: April 13, 2004Assignee: NEC CorporationInventors: Kazuhiko Hayashi, Keishi Ohashi, Nobuyuki Ishiwata, Masafumi Nakada, Eizo Fukami, Kiyokazu Nagahara, Hiroaki Honjo, Shinsaku Saitoh
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Patent number: 6721145Abstract: 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.Type: GrantFiled: January 2, 2002Date of Patent: April 13, 2004Assignee: International Business Machines CorporationInventor: Robert S. Beach
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Publication number: 20040060166Abstract: This invention describes a spin valve based magnetic read head that is suitable for use with ultra-high recording densities along with a process for manufacturing it. This process produces a product that is free of conductor lead bridging and conductor lead fencing. A key sub-process of the present invention is the deposition of a first capping layer through DC sputtering followed by, without breaking vacuum, a lead overlay layer This is followed by deposition, also by DC sputtering, of a second capping layer which is patterned so that it becomes a hard mask. Then, using this hard mask, the lead overlay layer is removed from the center of the structure by means of ion beam etching. Hard bias and conductor lead layers are then formed inside parallel trenches with the use of liftoff processes.Type: ApplicationFiled: September 30, 2003Publication date: April 1, 2004Applicant: HEADWAY TECHNOLOGIES, INC.Inventors: Cheng T. Horng, Ru-Ying Tong, Kochan Ju
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Publication number: 20040042129Abstract: 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.Type: ApplicationFiled: June 9, 2003Publication date: March 4, 2004Inventors: Tetsuya Mizuguchi, Masanori Hosomi, Kazuhiro Ohba, Kazuhiro Beesho, Yutaka Higo, Tetsuya Yamamoto, Takeyuki Sone, Hiroshi Kano
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Patent number: 6694604Abstract: A merged magnetic head has a top first pole tip layer and a bottom second pole tip layer which are located entirely between an air bearing surface and a coil layer. A write gap layer separates the pole tip layers from one another at the ABS. A zero throat height (ZTH) defining layer is located adjacent the top gap layer between the pole tip layers and is recessed from the ABS so as to further separate the pole tip layers from one another at a location recessed from the ABS so as to define the zero throat height of the write head where the first and second pole pieces first commence to separate from one another after the ABS.Type: GrantFiled: March 4, 2003Date of Patent: February 24, 2004Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventor: Hugo Alberto Emilio Santini
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Publication number: 20040027733Abstract: A magnetoresistive element includes a pair of ferromagnetic layers and a non-magnetic layer arranged between the ferromagnetic layers. At least one of the ferromagnetic layers has a composition expressed by (MxLy)100−zRz at the interface with the non-magnetic layer. The non-magnetic layer includes at least one element selected from the group consisting of B, C, N, O, and P. Here, M is FeaCobNic, L is at least one element selected from the group consisting of Pt, Pd, Ir, and Rh, R is an element that has a lower free energy to form a compound with the element of the non-magnetic layer that is at least one selected from the group consisting of B, C, N, O, and P than does any other element included in the composition as M or L, and a, b, c, x, y, and z satisfy a+b+c=100, a≧30, x+y=100, 0<y≦35, and 0.1≦z≦20. This element can provide a high MR ratio. A method for manufacturing a magnetoresistive element includes a first heat treatment process at 200° C.Type: ApplicationFiled: June 27, 2003Publication date: February 12, 2004Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.Inventors: Nozomu Matsukawa, Masayoshi Hiramoto, Akihiro Odagawa, Yasunari Sugita, Mitsuo Satomi, Yoshio Kawashima
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Publication number: 20040027732Abstract: A magnetic read head for use in a magnetic data storage and retrieval system is disclosed. The read head is typically a giant magnetoresistive (GMR) spin valve read sensor with a portion of the GMR spin valve read sensor implanted with ions. The implanted ions improve the GMR sensor's sensitivity to changes in resistance by increasing the resistance of inefficient or ineffective portions of the sensor. The invention is also directed to methods of making GMR read sensors.Type: ApplicationFiled: October 17, 2002Publication date: February 12, 2004Inventors: Brian Kelly, Kevin John Duddy, Alan Johnston, William O'Kane
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Patent number: 6687976Abstract: The invention provides a method of manufacturing a magnetic head slider and fixing a bar which improves fabrication accuracy without increasing manufacturing costs. After thin film magnetic head devices are formed on a wafer, the wafer is cut into bars each including two or more magnetic head sliders. The bars are carried and mounted onto a suction plater. A surface of each bar to be processed is brought into direct contact with a suction surface of the suction plate, and is positioned in a plane parallel to the suction surface. An adhesive is applied to the surface of a support substrate. The surfaces opposite to the surfaces to be processed are pressed against the adhesive. The adhesive is allowed to set. Adhesive thickness varies according to variations in thicknesses of the bars. Therefore, the surfaces of the bars to be processed can be kept aligned with a reference plane.Type: GrantFiled: September 19, 2000Date of Patent: February 10, 2004Assignee: TDK CorporationInventors: Akinori Koyama, Kazuhiro Kobayashi
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Patent number: 6679762Abstract: A method is disclosed for precision control of pole tip recession of magnetic recording heads. This is achieved by first constructing the head so that the thermal expansion coefficient of the recording head is different from the thermal expansion coefficient of the overcoat. Then the recording head is heated during the lapping process of the slider and recording head. The average and distribution of the recession between the overcoat and the recording head pole tips are improved.Type: GrantFiled: April 19, 2001Date of Patent: January 20, 2004Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Joseph John Fatula, Jr., Hans-Peter Nickel
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Patent number: 6634087Abstract: A spin valve based magnetic read head that is suitable for use with ultra-high recording densities is described along with a process for manufacturing it. This produces a product that is free of conductor lead bridging and conductor lead fencing. A key sub-process is the deposition of a first capping layer through DC sputtering followed by, without breaking vacuum, a lead overlay layer This is followed by deposition, also by DC sputtering, of a second capping layer which is patterned so that it becomes a hard mask. Then, using this hard mask, the lead overlay layer is removed from the center of the structure by means of ion beam etching. Hard bias and conductor lead layers are then formed inside parallel trenches without the use of liftoff processes.Type: GrantFiled: December 26, 2000Date of Patent: October 21, 2003Assignee: Headway Technologies, Inc.Inventors: Cheng T. Horng, Ru-Ying Tong, Kochan Ju
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Publication number: 20030192168Abstract: A method for forming a bottom spin valve sensor having a synthetic antiferromagnetic pinned (SyAP) layer, antiferromagnetically coupled to a pinning layer, in which one of the layers of the SyAP is formed as a three layer lamination that contains a specularly reflecting oxide layer of FeTaO. The sensor formed according to this method has an extremely high GMR ratio and exhibits good pinning strength.Type: ApplicationFiled: May 13, 2003Publication date: October 16, 2003Applicant: HEADWAY TECHNOLOGIES, INC.Inventors: Min Li, Simon H. Liao, Masashi Sano, Kiyoshi Noguchi, Kochan Ju, Cheng T. Horng
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Publication number: 20030179519Abstract: 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.Type: ApplicationFiled: January 16, 2003Publication date: September 25, 2003Inventor: Naoya Hasegawa
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Patent number: 6606781Abstract: An apparatus and method is disclosed for an enhanced double tunnel junction sensor which utilizes an enhancement layer(s) to enhance magnetoresistance (MR coefficient) and resonant tunneling. Additionally, a combined read/write head and disk drive system is disclosed utilizing the enhanced double tunnel junction sensor of the present invention. The enhancement layers improve the resonant tunneling and boost the MR coefficient to achieve a higher tunnel magnetoresistance (TMR) for the structure with applied dc bias. This is accomplished by using enhancement layers that create a quantum well between the enhancement layer and the pinned layer, which causes resonance, enhancing the tunneling electrons. By doing this, the tunneling constraints on the free layer are decoupled, allowing the free layer to be made thicker which results in reducing or eliminating free layer magnetic saturation caused by an external magnetic source.Type: GrantFiled: October 23, 2000Date of Patent: August 19, 2003Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventor: Hardayal Singh Gill
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Publication number: 20030151859Abstract: A magnetoresistive effect element which is easy to manufacture and in which a sense current is prevented from bypassing a barrier layer is provided. Also provided are a method for manufacturing the element and a magnetic recording apparatus utilizing the element. This magnetoresistive effect element utilizes an MTJ film which comprises, for forming its basic structure, a free layer, a barrier layer, a pinned layer and a pinning layer, wherein an oxide or a nitride layer is formed by oxidizing or nitriding metallic materials constituting the pinned layer and pinning layer.Type: ApplicationFiled: February 3, 2003Publication date: August 14, 2003Applicant: NEC CORPORATIONInventors: Kazuhiko Hayashi, Keishi Ohashi, Nobuyuki Ishiwata, Masafumi Nakada, Eizo Fukami, Kiyokazu Nagahara, Hiroaki Honjou, Shinsaku Saitoh
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Patent number: 6593736Abstract: The invention includes a method and apparatus repairing read heads of a merged magnetoresistive read-write head without the use of external magnets nor the exclusive use of read bias current to heat the read head.Type: GrantFiled: February 11, 2002Date of Patent: July 15, 2003Inventors: Eun Kyu Jang, Hyung Jai Lee
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Patent number: 6591479Abstract: A production method for a spin-valve type magnetoresistive element comprising laminating an antiferromagnetic layer, a pinned magnetic layer, a non-magnetic electrically conductive layer, a free magnetic layer, and a second antiferromagnetic layer. The second antiferromagnetic layer is located on the free magnetic layer and orients the magnetization direction of the free magnetic layer. In this method, a first thermal treatment is performed at a first temperature of ordering a crystal structure of the first antiferromagnetic layer or at a second temperature lower than a second blocking temperature of the second antiferromagnetic layer. After the first thermal treatment, a second thermal treatment is performed at a third temperature lower than a first blocking temperature of the first antiferromagnetic layer but higher than said second blocking temperature of the second antiferromagnetic layer.Type: GrantFiled: March 29, 2000Date of Patent: July 15, 2003Assignee: Alps Electric Co., Ltd.Inventors: Yukie Nakazawa, Masamichi Saito, Naoya Hasegawa, Akihiro Makino
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Publication number: 20030123198Abstract: 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.Type: ApplicationFiled: August 30, 2002Publication date: July 3, 2003Inventors: Nobuhiro Sugawara, Masatoshi Yoshikawa, Hiroyuki Ohmori
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Patent number: 6581272Abstract: A method for forming a bottom spin valve sensor having a synthetic antiferromagnetic pinned (SyAP) layer, antiferromagnetically coupled to a pinning layer, in which one of the layers of the SyAP is formed as a three layer lamination that contains a specularly reflecting oxide layer of FeTaO. The sensor formed according to this method has an extremely high GMR ratio and exhibits good pinning strength.Type: GrantFiled: January 4, 2002Date of Patent: June 24, 2003Assignee: Headway Technologies, Inc.Inventors: Min Li, Simon H. Liao, Masashi Sano, Kiyoshi Noguchi, Kochan Ju, Cheng T. Horng
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Publication number: 20030095363Abstract: A high performance specular free layer bottom spin valve is disclosed. This structure made up the following layers: NiCr/MnPt/CoFe/Ru/CoFe/Cu/free layer/Cu/Ta or TaO/Al2O3. A key feature is that the free layer is made of a very thin CoFe/NiFe composite layer. Experimental data confirming the effectiveness of this structure is provided, together with a method for manufacturing it and, additionally, its longitudinal bias leads.Type: ApplicationFiled: November 12, 2002Publication date: May 22, 2003Applicant: HEADWAY TECHNOLOGIES, INC.Inventors: Cheng T. Horng, Mao-Min Chen, Min Li, Ru-Ying Tong
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Patent number: 6560852Abstract: Disc drives are made with an actuator designed with at least one asymmetrical arm having two masses that move out of phase. The arm is modified by removing a portion of the higher-energy (longitudinal) side, the one with the greater total time-averaged strain energy. This modification reduces the phase difference between the first and the second arm, particularly for a relevant frequency range of interest. Disc drives made by this method exhibit a generally reduced out-of-phase motion, enhancing performance during seeking and track following, especially for arms with two heads that interact with surfaces of opposing discs.Type: GrantFiled: February 6, 2001Date of Patent: May 13, 2003Assignee: Seagate Technology LLCInventors: Andre Liem, Joseph Lau, CheeWai Seetoh, Jierapipatanakul Niroot
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Patent number: 6557242Abstract: A merged magnetic head has a top first pole tip layer and a bottom second pole tip layer which are located entirely between an air bearing surface and a coil layer. A write gap layer separates the pole tip layers from one another at the ABS. A zero throat height (ZTH) defining layer is located adjacent the top gap layer between the pole tip layers and is recessed from the ABS so as to further separate the pole tip layers from one another at a location recessed from the ABS so as to define the zero throat height of the write head where the first and second pole pieces first commence to separate from one another after the ABS.Type: GrantFiled: December 27, 1999Date of Patent: May 6, 2003Assignee: International Business Machines CorporationInventor: Hugo Alberto Emilio Santini
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Publication number: 20030053267Abstract: A method for forming top and bottom spin valve sensors and the sensors so formed, the sensors having a strongly coupled SyAP pinned layer and an ultra-thin antiferromagnetic pinning layer. The two strongly coupled ferromagnetic layers comprising the SyAP pinned layer in the top valve configuration are separated by a Ru spacer layer approximately 3 angstroms thick, while the two layers in the bottom spin valve configuration are separated by a Rh spacer layer approximately 5 angstroms thick. This allows the use of an ultra thin MnPt antiferromagnetic pinning layer of thickness between approximately 80 and approximately 150 angstroms. The sensor structure produced thereby is suitable for high density applications.Type: ApplicationFiled: September 17, 2001Publication date: March 20, 2003Applicant: Headway Technologies, Inc.Inventors: Cheng T. Horng, Kochan Ju, Mao-Min Chen, Min Li, Ru-Ying Tong, Simon Liao
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Publication number: 20030011941Abstract: A second antiferromagnetic layer formed on a free magnetic layer has a blocking temperature lower than that of a first antiferromagnetic layer. The exchange anisotropic magnetic field between the free magnetic layer and the second antiferromagnetic layer is smaller than the exchange anisotropic magnetic field between the first antiferromagnetic layer and the pinned magnetic layer. By applying an annealing treatment utilizing the blocking temperature difference between the first and second antiferromagnetic layers, the magnetization direction and the strength of the pinned magnetic layer and the free magnetic layer can be controlled appropriately.Type: ApplicationFiled: March 29, 2000Publication date: January 16, 2003Inventors: Yukie Nakazawa, Masamichi Saito, Naoya Hasegawa, Akihiro Makino
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Patent number: 6500570Abstract: A spin-valve magnetoresistive element includes an antiferromagnetic layer, a first pinned magnetic layer, a nonmagnetic interlayer, a second pinned magnetic layer, a nonmagnetic conductive layer, a free magnetic layer, a pair of longitudinal biasing layers, and a pair of lead layers. When a detecting current is applied from the lead layers, the magnetization vector of the free magnetic layer is aligned in a direction intersecting the magnetization vector of the second pinned magnetic layer, and the magnetization vector of the second pinned magnetic layer is tilted by an angle &thgr; from the normal of a track width direction toward a direction opposite to a longitudinal biasing magnetic field, in order to reduce asymmetry of the output.Type: GrantFiled: December 5, 2000Date of Patent: December 31, 2002Assignee: Alps Electric Co., Ltd.Inventors: Naoya Hasegawa, Fumihito Koike, Yosuke Ide
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Patent number: 6493196Abstract: A spin-valve magnetoresistive sensor includes a free layer of a ferromagnetic material, a pinned layer provided on the free layer and a pinning layer of an anti-ferromagnetic material provided on the pinned layer, the anti-ferromagnetic material being an ordered alloy containing manganese. The pinned layer includes a first pinned layer of a ferromagnetic material, a second pinned layer of a ferromagnetic material provided on the first pinned layer and an intermediate layer interposed between the first and second pinned layers such that the first and second pinned layers establish a super-exchange interaction in an anti-parallel manner. The second pinned layer has a magnetic moment smaller than a magnetic moment of the first pinned layer.Type: GrantFiled: December 29, 1999Date of Patent: December 10, 2002Assignee: Fujitsu Ltd.Inventors: Kenji Noma, Hitoshi Kanai, Junichi Kane, Kenichi Aoshima
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Publication number: 20020174533Abstract: This invention describes a spin valve based magnetic read head that is suitable for use with ultra-high recording densities along with a process for manufacturing it. This process produces a product that is free of conductor lead bridging and conductor lead fencing. A key sub-process of the present invention is the deposition of a first capping layer through DC sputtering followed by, without breaking vacuum, a lead overlay layer This is followed by deposition, also by DC sputtering, of a second capping layer which is patterned so that it becomes a hard mask. Then, using this hard mask, the lead overlay layer is removed from the center of the structure by means of ion beam etching. Hard bias and conductor lead layers are then formed inside parallel trenches without the use of liftoff processes.Type: ApplicationFiled: December 26, 2000Publication date: November 28, 2002Applicant: Headway Technologies, Inc.Inventors: Cheng T. Horng, Ru-Ying Tong, Kochan Ju
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Patent number: 6478884Abstract: A manufacturing method of a thin-film magnetic head with a spin valve effect MR read sensor includes a temperature-annealing step of firmly fixing the direction of the pinned magnetization in the spin valve effect MR sensor. The temperature-annealing step is executed by a plurality of times.Type: GrantFiled: May 29, 2001Date of Patent: November 12, 2002Assignee: TDK CorporationInventors: Koji Shimazawa, Manabu Ohta, Tetsuro Sasaki
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Patent number: 6469878Abstract: Methods of fabricating spin valve sensors in accordance with the invention include forming a pinning layer from an antiferromagnetic material and forming a synthetic antiferromagnet adjacent the pinning layer. A free ferromagnetic layer is formed, and exchange tabs are formed adjacent outer portions of the free ferromagnetic layer for biasing the free layer. The exchange tabs are formed from the same antiferromagnetic material as the first pinning layer. Then, the magnetic moments of the synthetic antiferromagnet are set, and the magnetic moment of the free ferromagnetic layer is biased, during a single anneal in the presence of a single magnetic field.Type: GrantFiled: February 8, 2000Date of Patent: October 22, 2002Assignee: Seagate Technology LLCInventors: Anthony M. Mack, Zheng Gao, Nurul Amin, Sining Mao, Richard Michel