Plural Magnetic Layers Of Same Empirical Composition, Each With Different Structure (e.g., Differing Crystalline Lattice, Atomic Structure, Etc.) Patents (Class 428/830)
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Patent number: 10978103Abstract: A magnetic recording medium includes: a substrate; an underlayer; and a magnetic layer including an alloy having a L10 structure and a (001) orientation, wherein the substrate, the underlayer, and the magnetic layer are stacked in the recited order, and wherein the magnetic layer has a granular structure and includes a carbon hydride, a boron hydride, or a boron nitride hydride.Type: GrantFiled: May 9, 2019Date of Patent: April 13, 2021Assignee: SHOWA DENKO K.K.Inventors: Takayuki Fukushima, Kazuya Niwa, Lei Zhang, Hisato Shibata, Takehiro Yamaguchi, Chen Xu, Tetsuya Kanbe, Tomoo Shige
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Patent number: 9034492Abstract: Systems and methods for controlling the damping of magnetic media for heat assisted magnetic recording are provided. One such system includes a heat sink layer, a growth layer on the heat sink layer, a magnetic recording layer on the growth layer, where the growth layer is configured to facilitate a growth of a preselected crystalline structure of the magnetic recording layer, and a capping magnetic recording layer on the magnetic recording layer, the capping recording layer including a first material configured to increase a damping constant of the capping recording layer to a first preselected level.Type: GrantFiled: January 11, 2013Date of Patent: May 19, 2015Assignee: WD Media, LLCInventors: Michael L. Mallary, Gerardo A. Bertero, Kumar Srinivasan
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Publication number: 20140342188Abstract: An apparatus includes a substrate and a magnetic layer coupled to the substrate. The magnetic layer includes an alloy that has magnetic hardness that is a function of the degree of chemical ordering of the alloy. The degree of chemical ordering of the alloy in a first portion of the magnetic layer is greater than the degree of chemical ordering of the alloy in a second portion of the magnetic layer, and the first portion of the magnetic layer is closer to the substrate than the second portion of the magnetic layer.Type: ApplicationFiled: August 5, 2014Publication date: November 20, 2014Inventors: Yingguo Peng, Xiaowei Wu, Ganping Ju, Bin Lu
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Patent number: 8883327Abstract: Provided is a magnetic recording medium achieving both of reduction in switching field distribution and reduction in switching field intensity by high-frequency magnetic field, thus enabling high-density recording. Magnetic grains of the magnetic recording medium are made up of a recording layer and a resonance layer. The resonance layer is disposed closer to a protective layer 5 than the recording layer, and a magnetic material of the recording layer has anisotropy field 1.2 times or more anisotropy field of a magnetic material of the resonance layer. The magnetic material of the recording layer has saturation magnetization substantially equal to saturation magnetization of the magnetic material of the resonance layer. At the entire resonance layer and a part of the recording layer, the magnetic grains are separated from surrounding magnetic grains by a nonmagnetic material, and at a part of the recording layer, the magnetic grains are coupled with surrounding magnetic grains.Type: GrantFiled: March 13, 2013Date of Patent: November 11, 2014Assignee: Hitachi, Ltd.Inventors: Yoshiyuki Hirayama, Masukazu Igarashi, Katsuro Watanabe
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Patent number: 8877359Abstract: Provided are a magnetic disk comprising a granular magnetic recording layer which causes less noise even with a recording capacity thereof of 250 G or more bits per square inch; and a method for manufacturing the same. The magnetic disk according to the present invention comprises: a granular magnetic recording layer (20) which is formed on a disk substrate 10 directly or via an intermediate layer and which has non-magnetic regions between granular columnar particles; and an auxiliary recording layer (22) which is formed on the granular magnetic recording layer 20 and which causes exchange interaction among the granular columnar particles, wherein the auxiliary recording layer (22) contains 0.1 to 3 moles of oxygen.Type: GrantFiled: December 7, 2009Date of Patent: November 4, 2014Assignee: WD Media (Singapore) Pte. Ltd.Inventors: Chiyo Saito, Tokichiro Sato, Takenori Kajiwara
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Patent number: 8871368Abstract: A perpendicular magnetic recording medium with SNR improved by reducing noise due to an auxiliary recording layer so that a higher recording density can be achieved. The perpendicular magnetic recording medium 100 includes a base, at least a magnetic recording layer 122 having a granular structure in which a non-magnetic grain boundary portion is formed between crystal particles grown in a columnar shape; a non-magnetic split layer 124 disposed on the magnetic recording layer 122 and containing Ru and oxygen; and an auxiliary recording layer 126 that is disposed on the split layer 124 and that is magnetically approximately continuous in an in-plane direction of a main surface of the base 110.Type: GrantFiled: September 16, 2009Date of Patent: October 28, 2014Assignee: WD Media (Singapore) Pte. Ltd.Inventors: Takahiro Onoue, Teiichiro Umezawa, Toshiaki Tachibana, Masafumi Ishiyama
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Patent number: 8802247Abstract: A medium having high medium S/N and excellent corrosion resistance is achieved. In one embodiment, an adhesion layer, a soft magnetic layer, an intermediate layer, a magnetic recording layer, and a protective layer are deposited, in order, on a substrate. The soft magnetic underlayer consists at least of two soft magnetic layers, the first soft magnetic layer formed on the recording layer side being composed of an amorphous alloy containing 85 at. % or less of Co, and the second soft magnetic layer formed on the substrate side being composed of an alloy containing more than 85 at. % of Co.Type: GrantFiled: October 17, 2006Date of Patent: August 12, 2014Assignee: HGST Netherlands B.V.Inventors: Hiroyuki Matsumoto, Mitsuhiro Shoda, Reiko Arai, Yuzuru Hosoe, Katsumi Mabuchi
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Patent number: 8758911Abstract: A perpendicular magnetic recording medium is disclosed that includes a substrate, a main recording layer, a reinforcing layer, and a continuous layer which are overlaid in this order on the substrate. The reinforcing layer is provided between the main recording layer and the continuous layer so as to improve the S/N ratio of the magnetic recording medium and reduce the write fringing effect. The reinforcing layer has a granular structure. The saturation magnetization Ms of the reinforcing layer is higher than the saturation magnetization of the main recording layer.Type: GrantFiled: May 30, 2008Date of Patent: June 24, 2014Assignee: WD Media (Singapore) Pte. Ltd.Inventors: Yoshiaki Sonobe, Kong Kim
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Patent number: 8728637Abstract: A corrosion-resistant granular magnetic recording medium with improved recording performance comprises a non-magnetic substrate having a surface; and a layer stack on the substrate surface, including, in order from the surface: a granular magnetic recording layer; an intermediate magnetic de-coupling layer; and a corrosion preventing magnetic cap layer. The intermediate magnetic de-coupling layer has an optimal thickness and/or composition for: (1) promoting magnetic exchange de-coupling between the granular magnetic recording layer and the magnetic cap layer; and (2) reducing the dynamic closure field (Hcl) for determining writeability and eraseability of the medium. Grain boundaries of the magnetic cap layer are substantially oxide-free, and have a greater density and lower average porosity and surface roughness than those of the granular magnetic recording layer.Type: GrantFiled: January 14, 2010Date of Patent: May 20, 2014Assignee: Seagate Technology LLCInventors: Michael Zyee-Shan Wu, Mason Lu, Kueir W. Chour, Connie C. Liu, Edward T. Yen, Lynn Li, Steve Hwang
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Patent number: 8685547Abstract: Aspects are directed to recording media with enhanced magnetic properties for improved writability. Examples can be included or related to methods, systems and components that allow for improved writability while reducing defects so as to obtain uniform magnetic properties such as uniformly high anisotropy and narrow switching field distribution. Some examples include a recording medium with an exchange tuning layer inserted between the hard layer and the soft, semi-soft or thin semi-hard layer so as to maximize the writability improvement of the media. Preferably, the exchange tuning layer is granular and reduces or optimizes the vertical coupling between the hard layer and the soft, semi-soft or semi-hard layer of a magnetic recording or storing device.Type: GrantFiled: February 19, 2009Date of Patent: April 1, 2014Assignee: Seagate Technology LLCInventors: Bo Bian, Shoutao Wang, Weilu Xu, Abebe Hailu, Miaogen Lu, Charles C. Chen, Thomas Patrick Nolan, Alexander Yulievich Dobin
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Patent number: 8679654Abstract: Surface flatness of magnetic recording medium to which a magnetic recording layer made of L10 FePt magnetic alloy thin film, with distance between a magnetic head and a magnetic recording medium sufficiently reduced. The magnetic recording layer includes: magnetic layers containing a magnetic alloy including Fe and Pt as principal materials; and one non-magnetic material selected from carbon, oxide and nitride. The first magnetic layer disposed closer to a substrate has a granular structure in which magnetic alloy grains including FePt alloy as the principal material are separated from grain boundaries including the non-magnetic material as the principal material. The second magnetic layer disposed closer to the surface than the first magnetic layer is fabricated so as to have a homogeneous structure in which an FePt alloy and the non-magnetic material are mixed in a state finer than diameters of the FePt magnetic alloy grains in the first magnetic layer.Type: GrantFiled: February 13, 2012Date of Patent: March 25, 2014Assignee: Hitachi, Ltd.Inventors: Hiroaki Nemoto, Ikuko Takekuma, Kimio Nakamura, Junichi Sayama
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Patent number: 8658292Abstract: Systems and methods for controlling the damping of magnetic media for magnetic recording are described. One such system includes a magnetic media structure for magnetic recording, the media structure including at least one base layer including an interlayer, a bottom magnetic recording layer positioned on the interlayer, and an exchange coupling layer positioned on the bottom layer; and a capping magnetic recording layer positioned on the at least one base layer, the capping recording layer including a first material configured to increase a damping constant of the capping recording layer to a first preselected level.Type: GrantFiled: June 10, 2011Date of Patent: February 25, 2014Assignee: Western Digital Technologies, Inc.Inventors: Michael L. Mallary, Gerardo A. Bertero
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Patent number: 8603650Abstract: A magnetic disk 10 for use in perpendicular magnetic recording has at least a magnetic recording layer on a substrate 1. The magnetic recording layer is composed of a ferromagnetic layer 5 of a granular structure containing silicon (Si) or an oxide of silicon (Si) between crystal grains containing cobalt (Co), a stacked layer 7 having a first layer containing cobalt (Co) or a Co alloy and a second layer containing palladium (Pd) or platinum (Pt), and a spacer layer 6 interposed between the ferromagnetic layer 5 and the stacked layer 7. After forming the ferromagnetic layer 5 on the substrate 1 by sputtering in an argon gas atmosphere, the stacked layer 7 is formed by sputtering in the argon gas atmosphere at a gas pressure lower than that used when forming the ferromagnetic layer 5.Type: GrantFiled: June 29, 2005Date of Patent: December 10, 2013Assignee: WD Media (Singapore) Pte. Ltd.Inventors: Yoshiaki Sonobe, Teiichiro Umezawa, Chikara Takasu
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Patent number: 8603649Abstract: A perpendicular magnetic recording medium includes a magnetic recording layer 22 having a granular structure composed of crystal grains containing cobalt (Co) and grown in a columnar shape and a grain boundary portion comprising a nonmagnetic substance and formed between the crystal grains, and a continuous layer 24 of a thin film magnetically continuous in a film plane direction. The continuous layer 24 includes a plurality of layers 24a and 24b containing cobalt, chromium (Cr), and platinum (Pt). Among the layers, the layer 24a nearer to the magnetic recording layer has a greater chromium content.Type: GrantFiled: October 6, 2008Date of Patent: December 10, 2013Assignee: WD Media (Singapore) Pte. Ltd.Inventor: Takahiro Onoue
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Patent number: 8592061Abstract: In order to provide a magnetic recording medium having excellent electromagnetic conversion characteristics, a magnetic recording medium (10) is provided with a substrate (12), and a magnetic recording layer (20) formed on the substrate (12). The magnetic recording layer (20) is provided with a granular layer (32), i.e., a magnetic layer, including magnetic grains and a nonmagnetic material surrounding the magnetic grains in a section parallel to the main surface of the substrate. The ratio of the long diameter to the short diameter of each magnetic grain contained in the granular layer (32) is calculated in the section. In the histogram of such ratio, a half width at half maximum of the histogram is 0.6 or less and the variance of grain diameters of the magnetic grains in the section is 20% or less of the average grain diameter of the magnetic grains.Type: GrantFiled: September 26, 2007Date of Patent: November 26, 2013Assignee: WD Media (Singapore) Pte. Ltd.Inventors: Takahiro Onoue, Akira Shimada
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Patent number: 8580409Abstract: Perpendicular magnetic recording (PMR) media and methods of fabricating PMR media are described. The PMR media includes, among other layers, an underlayer, a first onset layer on the underlayer, a second onset layer on the first onset layer, and a perpendicular magnetic recording layer on the second onset layer. The second onset layer has a magnetic moment which is higher than both a magnetic moment of the first onset layer and a magnetic moment of the perpendicular magnetic recording layer.Type: GrantFiled: November 9, 2009Date of Patent: November 12, 2013Assignee: HGST Netherlands B.V.Inventors: Xiaoping Bian, Jack Jyh-Kau Chang, Zhupei Shi
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Patent number: 8580410Abstract: An object of the present invention is to provide a perpendicular magnetic recording medium 100 including a magnetic recording layer 122, the medium in which a particle diameter of crystal grains in the magnetic recording layer 122 of a two-layer structure is so designed as to improve an SNR while a high coercive force is maintained.Type: GrantFiled: March 26, 2009Date of Patent: November 12, 2013Assignee: WD Media (Singapore) Pte. Ltd.Inventor: Takahiro Onoue
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Patent number: 8557408Abstract: A recording medium having a substrate, a first soft magnetic underlayer, a second soft magnetic underlayer and a perpendicular magnetic recording layer without a spacer layer between the first and second soft magnetic underlayers is disclosed.Type: GrantFiled: April 3, 2012Date of Patent: October 15, 2013Assignee: Seagate Technology LLCInventors: Qixu Chen, Charles Brucker, Chung-Hee Chang, Tom Nolan, Samuel Dacke Harkness, IV
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Patent number: 8546000Abstract: A perpendicular magnetic disk that includes, a base 110, a granular magnetic layer 160, and a auxiliary recording layer 180 disposed as an upper layer of the granular magnetic layer 160. The granular magnetic layer 160 has a granular structure in which a grain boundary portion is formed by segregation of a non-magnetic substance containing an oxide as a main component around magnetic particles containing a CoCrPt alloy grown in a columnar shape as a main component. The auxiliary recording layer 180 contains a CoCrPtRu alloy as a main component and has a film thickness of 1.5 nm to 4.0 nm. With this structure, the auxiliary recording layer can be thinned while maintaining the function thereof to improve SNR.Type: GrantFiled: April 28, 2011Date of Patent: October 1, 2013Assignee: WD Media, LLCInventor: Teiichiro Umezawa
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Patent number: 8529989Abstract: The present invention relates to a method for manufacturing a perpendicular magnetic recording medium including a nonmagnetic substrate, and at least a soft magnetic under layer, an orientation control layer, a magnetic recording layer constituted of two or more layers and a protective layer formed on the nonmagnetic substrate, the method including a step of forming a first magnetic recording layer having a granular structure constituted of ferromagnetic crystal grains and crystal grain boundaries made of a nonmagnetic oxide or nitride on the nonmagnetic substrate side, a step of forming a second magnetic recording layer constituted only of ferromagnetic crystal grains, a step of forming a surface unevenness control layer for decreasing surface unevenness of the first magnetic recording layer located between the first magnetic recording layer and the second magnetic recording layer, and a step of heating the nonmagnetic substrate so as to decrease a surface roughness Ra of the second magnetic recording layerType: GrantFiled: October 2, 2008Date of Patent: September 10, 2013Assignee: Showa Denko K.K.Inventors: Gohei Kurokawa, Yuzo Sasaki
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Patent number: 8507114Abstract: A magnetic stack includes multiple granular layers, at least one of the multiple granular layers is a magnetic layer that includes exchange coupled magnetic grains separated by a segregant having Ms greater than 100 emu/cc. Each of the multiple granular layers have anisotropic thermal conductivity.Type: GrantFiled: June 30, 2011Date of Patent: August 13, 2013Assignee: Seagate Technology LLCInventors: Yingguo Peng, Jan-Ulrich Thiele, Ganping Ju, Thomas Patrick Nolan, Yinfeng Ding, Alexander Qihong Wu
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Patent number: 8507115Abstract: According to one embodiment, a perpendicular magnetic recording medium includes a soft magnetic underlayer having an amorphous structure or a microcrystalline structure, a first seed layer comprised of a magnetic material having an fcc crystal structure including a CoFe alloy formed on a substrate side, and a second seed layer formed on the first seed layer, the second seed layer comprised of a nonmagnetic material having an fcc crystal structure including a NiW alloy. The medium also includes an intermediate layer comprised of Ru or an alloy thereof, a magnetic recording layer, and a protective layer, wherein the layers are sequentially stacked on a substrate in the foregoing order and the protective layer is closer to the substrate than the soft magnetic underlayer. Other embodiments of magnetic recording media, and methods of fabrication, are also described.Type: GrantFiled: September 14, 2009Date of Patent: August 13, 2013Assignee: HGST Netherlands B.V.Inventors: Reiko Arai, Niroyuki Nakagawa
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Patent number: 8460805Abstract: An apparatus includes a first magnetic layer including a plurality of grains. The first magnetic layer has a first anisotropy value. The apparatus also includes a second magnetic layer including a plurality of grains. The second magnetic layer has a second anisotropy value that is different than the first anisotropy value. The apparatus also includes an exchange tuning layer including a plurality of grains and located between the first and second magnetic layers. The exchange tuning layer has stronger inter-granular exchange coupling than the first and second magnetic layers. The exchange tuning layer has an anisotropy value less than the first and second anisotropy values.Type: GrantFiled: December 23, 2010Date of Patent: June 11, 2013Assignee: Seagate Technology LLCInventors: Kaizhong Gao, Yingguo Peng
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Patent number: 8440332Abstract: Embodiments of the present invention provide a perpendicular magnetic recording medium that reduces the noise of granular recording layers, obtains sufficient overwrite characteristic that suppresses an increase in the magnetic cluster size, and allows high-density recording. According to one embodiment, a perpendicular magnetic recording medium comprising substrate having thereon at least soft magnetic layer, nonmagnetic intermediate layer, a perpendicular recording layer and protective layer formed in that order. The perpendicular recording layer consists of three or more layers of first recording layer, a second recording layer, and a third recording layer from the side nearer to the substrate. The first recording layer and the second recording layer have a granular structure comprising a grain boundary of an oxide surrounding ferromagnetic crystal grains containing Co and Pt, and the third recording layer has a non-granular structure mainly comprising Co and not containing an oxide.Type: GrantFiled: April 8, 2009Date of Patent: May 14, 2013Assignee: HGST Netherlands B.V.Inventors: Ichiro Tamai, Kiwamu Tanahashi
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Patent number: 8404368Abstract: In some embodiments, an article comprising a first magnetic recording layer, the first magnetic recording layer including a granular layer having a first magnetic anisotropy and a multi-layer stack adjacent the granular layer, the multi-layer stack comprising one or more substantially magnetic film layers alternating with one or more polarization conductor layers, wherein the multi-layer stack has a second magnetic anisotropy that is greater than the first magnetic anisotropy.Type: GrantFiled: July 30, 2010Date of Patent: March 26, 2013Assignee: Seagate Technology LLCInventors: Zhong Wu, Shanghsien Rou
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Patent number: 8367228Abstract: A method for manufacturing a magnetic recording medium for perpendicular magnetic recording includes the steps of forming a first magnetic layer which has magnetic crystal grains exhibiting perpendicular magnetic anisotropy and nonmagnetic substances for magnetically separating the magnetic crystal grains from each other at grain boundaries of the magnetic crystal grains, forming a second magnetic layer which has magnetic grains exchange-coupled to the magnetic crystal grains, a grain boundary width of the magnetic grains being smaller than a grain boundary width of the magnetic crystal grains, and forming separation regions which magnetically separate tracks from each other in regions between the tracks of the magnetic recording medium in at least the second magnetic layer. The separation regions are disposed substantially only in the second magnetic layer of the first magnetic layer and the second magnetic layer.Type: GrantFiled: October 18, 2010Date of Patent: February 5, 2013Assignee: WD Media (Singapore) PTE. Ltd.Inventors: Yoshiaki Sonobe, Teiichiro Umezawa, Koichi Wago
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Patent number: 8329321Abstract: A perpendicular magnetic recording medium is disclosed that achieves improved recordability without deteriorating thermal stability by reducing the switching field. A perpendicular magnetic recording medium of the invention has a first magnetic recording layer and a second magnetic recording layer between with is interposed a coupling layer that ferromagnetically couples the two layers. The first and second magnetic recording layers satisfy an inequality Ku1T1>Ku2T2 in the case where Hk1 >Hk2 and an inequality Ku1T1<Ku2T2 in the case where Hk1<Hk2, where Hk1 and Hk2 are anisotropy magnetic fields, Ku1 and Ku2 are uniaxial anisotropy constants, and T1 and T2 are thicknesses of the first magnetic recording layer and the second recording layer, respectively. An exchange coupling energy between the magnetic recording layers is preferably at least 5×10?3 erg/cm2.Type: GrantFiled: July 1, 2005Date of Patent: December 11, 2012Assignee: Fuji Electric Co., Ltd.Inventors: Shunji Takenoiri, Yasushi Sakai
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Patent number: 8241766Abstract: An apparatus includes a plurality of bilayer structures positioned adjacent to each other, each of the bilayer structures including a first layer of magnetic material having a first Curie temperature and a second layer of magnetic material positioned adjacent to the first layer, wherein the second layer has a second Curie temperature that is lower than the first Curie temperature, and magnetic grains of the first layer are unstable when the second layer of magnetic material is heated above the second Curie temperature. The recording temperature is reduced due to the smaller switching volume achieved by using vertically decoupled laminations at elevated temperatures.Type: GrantFiled: August 8, 2007Date of Patent: August 14, 2012Assignee: Seagate Technology LLCInventors: Bin Lu, Ganping Ju
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Patent number: 8202636Abstract: A method is described for improving recording performance of a perpendicular media. The method includes controlling the anisotropy levels in different sublayers of the magnetic recording layers of the perpendicular media. Further, the different sublayers thicknesses can be altered to match the media to a particular head.Type: GrantFiled: December 23, 2008Date of Patent: June 19, 2012Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Gunn Choe, Yoshihiro Ikeda, Mohammad T. Mirzamaani, Kai Tang, Jinliu Wang
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Patent number: 8119263Abstract: A magnetic recording medium having a substrate, a first magnetic layer and a second magnetic layer, in this order, wherein an exchange coupling in the first magnetic layer is lower than an exchange coupling in the second magnetic layer, and the first and second magnetic layers are in a film stack so that magnetic grains in the first magnetic layer are exchange coupled by a pathway through the second magnetic layer is disclosed. A method of manufacturing a magnetic recording medium by obtaining a substrate, depositing a first magnetic layer at a first sputter gas pressure and depositing a second magnetic layer at a second sputter gas pressure, in this order, wherein the first sputter gas pressure is higher than the second sputter gas pressure, and an exchange coupling in the first magnetic layer is lower than an exchange coupling in the second magnetic layer is also disclosed.Type: GrantFiled: September 22, 2005Date of Patent: February 21, 2012Assignee: Seagate Technology LLCInventors: Thomas Patrick Nolan, Samuel D. Harkness, IV
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Patent number: 8007931Abstract: A perpendicular magnetic recording medium including: a substrate; a perpendicular magnetic recording layer disposed over the substrate; a soft magnetic underlayer disposed between the substrate and the perpendicular magnetic recording layer; a shunting layer disposed under the soft magnetic underlayer; and an isolation layer disposed between the soft magnetic underlayer and the shunting layer and providing magnetic isolation between the shunting layer and the other layers disposed over the shunting layer are provided. The shunting layer is magnetically separated from the other magnetic layers disposed over the shunting layer, and shunts a magnetic field generated by the magnetic domain walls of the soft magnetic underlayer such that the magnetic field cannot reach a magnetic head, thereby increasing a signal-to-noise ratio (SNR).Type: GrantFiled: January 26, 2007Date of Patent: August 30, 2011Assignee: Samsung Electronics Co., Ltd.Inventors: Hoo-san Lee, Chee-kheng Lim, Hoon-sang Oh, Sok-hyun Kong
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Patent number: 7976965Abstract: A magnetic recording medium comprises a nonmagnetic substrate on which is disposed at least a vertical magnetic layer. The vertical magnetic layer comprises at least three layers including a lower layer, an intermediate layer and an upper layer from the substrate side. The lower, intermediate and upper magnetic layers are bound by ferro-coupling and are constituted of magnetic particles which are columnar crystals extending continuously from the lower layer to the upper layer. A nonmagnetic layer is between the lower and intermediate magnetic layers or between the intermediate and upper magnetic layers. The upper layer has a magnetic anisotropic constant (Ku) from 0.8×106 to 4×106 (erg/cc), the intermediate layer has a magnetic anisotropic constant (Ku) from 2×106 to 7×106 (erg/cc) and the lower layer has a magnetic anisotropic constant (Ku) from 1×106 to 4×106 (erg/cc).Type: GrantFiled: August 20, 2009Date of Patent: July 12, 2011Assignee: Showa Denko K.K.Inventors: Kenji Shimizu, Junichi Kishimoto
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Patent number: 7923134Abstract: Embodiments of the present invention help to provide a discrete track medium for realizing a high track density in a low price by adopting a configuration, in which filling of a non-magnetic material into a guard band portion and smoothing processing of a medium surface are not required. According to one embodiment, a perpendicular magnetic recording medium, on the non-magnetic substrate, includes at least: a soft magnetic underlayer; a first recording layer including a crystal grain having a magnetic property and a non-magnetic grain boundary having an oxide, as a main component, surrounding the crystal grain; a second recording layer containing a ferromagnetic metal as a main component and not containing an oxide; and at least one non-magnetic layer provided between the first recording layer and the second recording layer.Type: GrantFiled: September 26, 2008Date of Patent: April 12, 2011Assignee: Hitachi Global Storage Technologies Netherlands BVInventors: Takayuki Ichihara, Masayoshi Shimizu
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Publication number: 20110038079Abstract: Perpendicular recording media with sublayers of dual oxide dopant magnetic materials are disclosed. The magnetic layer may comprise multiple sublayers of magnetic materials. In each sublayer, dual oxide dopants are incorporated. The compositions of the sublayers can be the same or different depending on the application. The magnetic layer may be deposited using a target comprising a mixture of CoPtCrB and dual oxides as dopants. The layer deposited with such targets can be the entire magnetic layer or a sublayer.Type: ApplicationFiled: August 13, 2009Publication date: February 17, 2011Applicant: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Gunn Choe, Mohammad T. Mirzamaani, Kai Tang, Jinliu Wang
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Patent number: 7833639Abstract: A magnetic recording medium for perpendicular magnetic recording includes a substrate, a granular layer having magnetic crystal grains exhibiting perpendicular magnetic anisotropy and nonmagnetic substances for magnetically separating the magnetic crystal grains from each other at grain boundaries of the magnetic crystal grains, and a continuous film layer having magnetic grains to be exchange-coupled to the magnetic crystal grains, the grain boundary width of the magnetic grains being smaller than that of the magnetic crystal grains, wherein separation regions for magnetically separating tracks from each other are disposed in regions between the tracks of the magnetic recording medium in at least the continuous film layer.Type: GrantFiled: September 27, 2007Date of Patent: November 16, 2010Assignee: WD Media (Singapore) Pte. Ltd.Inventors: Yoshiaki Sonobe, Teiichiro Umezawa, Koichi Wago
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Patent number: 7799445Abstract: A perpendicular magnetic recording medium including a soft magnetic underlayer. The perpendicular magnetic recording medium includes: a lower structural body including an anti-ferromagnetic layer; a first soft magnetic underlayer, a non-magnetic layer, and a second soft magnetic underlayer sequentially formed on the anti-ferromagnetic layer, where the thickness ratio of the second soft magnetic underlayer to that of the first soft magnetic underlayer is designed to be within specific range; and a recording layer formed on the second soft magnetic underlayer. Therefore, noise generated on the soft magnetic underlayer due to external magnetic fields of a magnetic head and a voice coil motor can be reduced greatly.Type: GrantFiled: June 30, 2006Date of Patent: September 21, 2010Assignee: Samsung Electronics Co., Ltd.Inventors: Hoon-sang Oh, Yong-su Kim, No-yeol Park, Hoo-san Lee, Chul-min Choi
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Patent number: 7736765Abstract: A granular perpendicular magnetic recording medium comprises a non-magnetic substrate and a granular perpendicular magnetic recording layer overlying the substrate, comprising a first granular perpendicular magnetic layer proximal the substrate and having a first saturation magnetization (Ms)1, and a second granular perpendicular magnetic layer distal the substrate and having a second, different saturation magnetization (Ms)2. Also disclosed is a method of fabricating the granular perpendicular magnetic recording medium.Type: GrantFiled: December 28, 2004Date of Patent: June 15, 2010Assignee: Seagate Technology LLCInventors: Zhong (Stella) Wu, Samuel Dacke Harkness, IV, Hans J. Richter, Alexander Yulievich Dobin
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Patent number: 7704613Abstract: A bit error rate is improved and, at the same time, an aging change due to thermal fluctuation is decreased. In one embodiment, a magnetic recording medium has first, second, third, and fourth magnetic layers stacked over the underlayer film on a substrate. The product (Brt2) of the residual magnetic flux density and film thickness of the second magnetic layer is smaller than the product (Brt3) of the residual magnetic flux density and film thickness of the third magnetic layer. The second magnetic layer has a thickness larger than that of the third magnetic layer and is anti-ferromagnetically coupled with the first magnetic layer by way of the first non-magnetic intermediate layer. The fourth magnetic layer is formed by way of a second non-magnetic intermediate layer above the third magnetic layer.Type: GrantFiled: May 1, 2006Date of Patent: April 27, 2010Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Hiroyuki Suzuki, Hidekazu Kashiwase, Akira Morinaga, Tatsuya Hinoue
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Patent number: 7704614Abstract: A method of fabricating a patterned magnetic recording medium, comprises steps of: (a) providing a layer stack including an uppermost non-magnetic interlayer; (b) forming a resist layer on the interlayer; (c) forming a first pattern comprising a first group of recesses extending through the resist layer and exposing a first group of spaced apart surface portions of the interlayer; (d) filling the first group of recesses with a layer of a hard mask material; (e) selectively removing the resist layer to form a second pattern comprising a second group of recesses extending through the hard mask layer and exposing a second group of spaced apart surface portions of the interlayer; and (f) filling the second group of recesses with a layer of a magnetically hard material forming a magnetic recording layer.Type: GrantFiled: October 20, 2006Date of Patent: April 27, 2010Assignee: Seagate Technology LLCInventors: Kim Y. Lee, Hong Ying Wang, Nobuo Kurataka, Christopher Formato, David S. Kuo, Dieter K. Weller
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Patent number: 7678476Abstract: A thin film structure comprises a first layer including a first plurality of grains of magnetic material having a first intergranular exchange coupling, and a second layer positioned adjacent to the first layer and including a second plurality of grains of magnetic material having a second intergranular exchange coupling, wherein the second intergranular exchange coupling is larger than the first intergranular exchange coupling and wherein the Curie temperature of the first layer is greater than the Curie temperature of the second layer. A data storage system including the thin film structure is also provided.Type: GrantFiled: January 20, 2006Date of Patent: March 16, 2010Assignee: Seagate Technology LLCInventors: Dieter Klaus Weller, Edward Charles Gage, Ganping Ju, Bin Lu
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Patent number: 7666529Abstract: A magnetic recording medium having a first magnetic layer, a spacer layer, and a second magnetic layer, in this order, wherein the spacer layer includes a non-magnetic layer and a thickness of the spacer layer is selected to establish anti-ferromagnetic coupling between the first magnetic layer and the second magnetic layer, and a thickness of both the first and second magnetic layers are less than a critical thickness for formation of stripe domains in the magnetic layers is disclosed.Type: GrantFiled: September 22, 2005Date of Patent: February 23, 2010Assignee: Seagate Technology LLCInventors: Erol Girt, Charles Frederick Brucker, Alexander Yulievich Dobin
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Patent number: 7618721Abstract: A master is provided for use in a magnetic printing process. Illustratively, the master is used for printing servo patterns on a magnetic recording medium. The master includes a substrate on which a magnetic underlayer material is disposed. A second magnetic material is disposed over the magnetic underlayer material so as to form a plurality of teeth adapted for use in the magnetic printing process. The teeth may be formed in the second material by an additive or subtractive process. Further, the dimensions of the teeth may be selected to optimize use of the master in a magnetic printing process on perpendicular media.Type: GrantFiled: April 1, 2005Date of Patent: November 17, 2009Assignee: Seagate Technology LLCInventor: Michael Mallary
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Patent number: 7592079Abstract: A magnetic disk for information storage that includes a substrate and an information layer for containing information. The information layer includes a upper (e.g., recording) and lower (e.g., stabilizing) layers. The information layer has a remanence-squareness-thickness-product (“Mrt”) that varies radially between first and second disk radii. At least one of the following conditions is true: (i) the information layer has a coercivity that is at least substantially constant between the first and second disk radii; (ii) the lower magnetic layer has a magnetic anisotropy energy of no more than about 1.5×106 erg/cm3; and (iii) the magnetic anisotropy energy of the upper magnetic layer is at least about 150% of the magnetic anisotropy energy of the lower magnetic layer.Type: GrantFiled: July 1, 2004Date of Patent: September 22, 2009Assignee: Seagate Technology LLCInventors: B. Ramamurthy Acharya, Gunn Choe
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Patent number: 7572526Abstract: A perpendicular magnetic recording system uses an exchange-spring type of perpendicular magnetic recording medium. The medium has a recording layer (RL) that includes a lower media layer (ML) and a multilayer exchange-spring layer (ESL) above the ML. The high anisotropy field (high-Hk) lower ML and the multilayer ESL are exchange-coupled across a coupling layer. The multilayer ESL has at least two ESLs separated by a coupling layer, with each of the ESLs having an Hk substantially less than the Hk of the ML. The exchange-spring structure with the multilayer ESL takes advantage of the fact that the write field magnitude and write field gradient vary as a function of distance from the write pole. The thicknesses and Hk values of each of the ESLs can be independently varied to optimize the overall recording performance of the medium.Type: GrantFiled: February 18, 2007Date of Patent: August 11, 2009Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Andreas Klaus Berger, Eric E. Fullerton, Byron Hassberg Lengsfield, III
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Patent number: 7572527Abstract: A perpendicular magnetic recording disk has an antiferromagnetically-coupled (AFC) recording layer (RL) comprised of lower and upper ferromagnetic layers, each having a hexagonal-close-packed (hcp) crystalline structure and perpendicular magnetic anisotropy, separated by an antiferromagnetically (AF) coupling layer, wherein the lower ferromagnetic layer (LFM) has substantially higher magnetic permeability than the upper ferromagnetic layer (UFM). The AFC RL is located on an actual exchange break layer (EBL) that separates the AFC RL from the disk's soft magnetic underlayer (SUL). The LFM functions as part of an “effective” exchange break layer (EBL) that also includes the actual EBL and the AF-coupling layer, thereby allowing the actual EBL to be made as thin as possible. The hcp LFM promotes the growth of the hcp UFM in the same way the actual EBL does so that its thickness contributes to the thickness necessary to grow the hcp UFM.Type: GrantFiled: May 24, 2005Date of Patent: August 11, 2009Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Eric E. Fullerton, Byron Hassberg Lengsfield, III, David Margulies
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Publication number: 20090197123Abstract: A storage device includes a storage medium, a controller and a read/write head. The storage medium includes a substrate with a plurality of nano-structures arranged in an ordered pattern on a surface of the substrate. The controller is coupled to the storage medium. The controller has a read structure that extends over the substrate and a positioner adapted to adjust a position of the read structure relative to the substrate. The read/write head is mounted on the read structure and positioned over the substrate during operation. The read/write head is adapted to read and to write information to and from the plurality of nano-structures.Type: ApplicationFiled: December 23, 2008Publication date: August 6, 2009Applicant: Seagate Technology LLCInventors: Joachim W. Ahner, Nisha Shukla, Dieter Weller
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Patent number: 7556871Abstract: Embodiments of the invention provide a perpendicular magnetic recording medium capable of reconciling a high recording density with high thermal stability, and having a high write-ability while maintaining high magnetic anisotropy energy. In one embodiment, a perpendicular magnetic recording medium has a soft-magnetic underlayer, and magnetic recording layers, and the magnetic recording layers comprises a first recording layer containing magnetic grains oriented in a direction normal to a medium plane, and a second recording layer containing magnetic grains tilted in a cross-track direction. There can be provided a perpendicular magnetic recording medium resistant to thermal fluctuation, small in medium noise, and excellent in write-ability.Type: GrantFiled: April 12, 2005Date of Patent: July 7, 2009Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Takayuki Ichihara, Atsushi Nakamura, Ichiro Tamai, Yuzuru Hosoe
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Patent number: 7537845Abstract: A perpendicular magnetic recording medium having a good thermal stability and a high recording density is provided. The perpendicular magnetic recording medium includes at least a first and a second perpendicular magnetic recording layer and a substrate supporting the first and the second perpendicular magnetic recording layers. The first and the second perpendicular magnetic recording layers have different physical/magnetic properties and are formed of materials that compensate the different physical/magnetic properties. The first and the second perpendicular magnetic recording layers are selected from a layer for improving perpendicular magnetic anisotropic energy (Ku), a layer for reducing the size of crystal grains, a layer for reducing the size of magnetic domains, a layer for increasing an SNR, a layer for improving signal output, a layer for reducing noise, a layer for improving the uniformity of crystal grain sizes, and a layer for improving the uniformity of magnetic domain sizes.Type: GrantFiled: March 1, 2006Date of Patent: May 26, 2009Assignee: Samsung Electronics Co., Ltd.Inventors: Byung-kyu Lee, Hoon-sang Oh, Kyung-jin Lee
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Patent number: 7531249Abstract: Provided is a magnetic recording medium having less noise and less recording degradation ascribed to “thermal fluctuation”. The magnetic recording medium has a magnetic recording film in which a magnetic region is dispersed in a non-magnetic region. In the magnetic recording medium, the magnetic region includes a hard magnetic layer which is a first magnetic portion made of a hard magnetic material with a coercive force and a soft magnetic layer which is a second magnetic portion made of a soft magnetic material with a coercive force smaller than that of the first magnetic portion, and the hard magnetic layer and the soft magnetic layer are laminated in a direction parallel to a film surface of the magnetic recording film.Type: GrantFiled: March 1, 2007Date of Patent: May 12, 2009Assignee: Canon Kabushiki KaishaInventor: Katsuya Oikawa
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Patent number: 7425377Abstract: A laminate structure is disclosed comprising multiple ferromagnetic layers achieving incoherent reversal while maintaining good SNR. A high magnetic moment density, low anisotropy field material may form a thin overlayer deposited over a high-anisotropy media layer. The media layer may have a lower magnetic moment density than the overlayer and have decoupled magnetic grains. A coupling layer may be interposed between the overlayer and the media layer to modulate the exchange there between, thereby reducing the pass-through of noise while still promoting incoherent reversal to achieve reduced write energy requirements.Type: GrantFiled: February 4, 2005Date of Patent: September 16, 2008Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Eric Edward Fullerton, Hoa Van Do, David Thomas Margulies, Natacha Supper