Three Or More Magnetic Layers On One Substrate Side Patents (Class 428/828.1)
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Patent number: 8582416Abstract: The heat-assisted magnetic recording medium of the present invention has a substrate, an under layer formed on the substrate, and a magnetic layer formed on the under layer, in which the magnetic layer includes an alloy having a L10 structure as a principle component, and the under layer is constituted by a first under layer made of an amorphous alloy or an alloy having a microcrystalline structure, a second under layer made of Cr or an alloy which contains Cr as a principle component and has a BCC structure, a third under layer made of a metal or an alloy having a BCC structure with a lattice constant of 2.98 ? or more, and a fourth under layer made of MgO.Type: GrantFiled: January 25, 2013Date of Patent: November 12, 2013Assignee: Showa Denko K.K.Inventors: Tetsuya Kanbe, Atsushi Hashimoto, Takayuki Fukushima
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Publication number: 20130280556Abstract: Provided herein, is an apparatus that includes a nonmagnetic substrate having a surface; and a plurality of overlying thin film layers forming a layer stack on the substrate surface. The layer stack includes a magnetically hard perpendicular magnetic recording layer structure and an underlying soft magnetic underlayer (SUL), wherein the sum of a magnetic thickness of the layer stack is a magnetic thickness of up to about 2 memu/cm?2.Type: ApplicationFiled: June 17, 2013Publication date: October 24, 2013Inventors: Li Tang, Weilu Xu, Youfeng Zheng, Shanghsien Rou, Connie Chunling Liu, Jianhua Xue, Li-Lien Lee, Thomas P. Nolan
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Patent number: 8557409Abstract: A perpendicular magnetic recording medium is disclosed that enables a high track density while maintaining good OW characteristics, SNR, and thermal stability. The medium includes a magnetic recording layer on a non-magnetic base, wherein the magnetic recording layer includes a first magnetic layer, a first exchange coupling control layer, a second magnetic layer, a third magnetic layer, and a fourth magnetic layer, in that order. It is preferable that when the perpendicular magnetic anisotropy constants of the first magnetic layer, second magnetic layer, third magnetic layer, and fourth magnetic layer are Ku1, Ku2, Ku3, and Ku4 respectively, relationships of Ku4>Ku3>Ku2 and Ku1>Ku3>Ku2 are satisfied.Type: GrantFiled: August 2, 2011Date of Patent: October 15, 2013Assignee: Fuji Electric Co., Ltd.Inventor: Sadayuki Watanabe
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Publication number: 20130258523Abstract: A magnetic recording medium of an embodiment includes: a substrate; a nonmagnetic base layer disposed on the substrate; a perpendicular magnetic recording layer disposed on the nonmagnetic base layer, having a hard magnetic recording layer, a nonmagnetic intermediate layer, and a soft magnetic recording layer, and divided into mutually separated plural regions; and a protective layer disposed on the perpendicular magnetic recording layer. The hard magnetic recording layer has an easy magnetization axis directed to a stack direction of the hard magnetic recording layer. The nonmagnetic intermediate layer contains one of C, ZnO, a carbide of Si, Ti, Ta or W, and a nitride of Si, Ti, Ta or W.Type: ApplicationFiled: December 21, 2012Publication date: October 3, 2013Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Tomoyuki MAEDA, Hiroyuki HIEDA, Yousuke ISOWAKI, Takuya SHIMADA
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Patent number: 8542569Abstract: A heat-assisted magnetic recording medium includes a substrate, a plurality of foundation layers, and a magnetic layer. The plurality of foundation layers are provided on the substrate and include a first layer containing MnO. The magnetic layer is provided on the plurality of layers and includes an alloy as a main ingredient. The alloy has an L10 structure.Type: GrantFiled: February 14, 2012Date of Patent: September 24, 2013Assignee: Showa Denko K.K.Inventors: Tetsuya Kanbe, Kazuya Niwa, Katsuya Hara
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Patent number: 8541116Abstract: A patterned perpendicular magnetic recording disk with discrete data islands of recording layer (RL) material includes a substrate, a patterned exchange bridge layer of magnetic material between the substrate and the islands, and an optional exchange-coupling control layer (CCL) between the exchange bridge layer and the islands. The exchange bridge layer has patterned pedestals below the islands. The exchange bridge layer controls exchange interactions between the RLs in adjacent islands to compensate the dipolar fields between islands, and the pedestals concentrate the flux from the write head. The disk may include a soft underlayer (SUL) of soft magnetically permeable material on the substrate and a nonmagnetic exchange break layer (EBL) on the SUL between the SUL and the exchange bridge layer. In a thermally-assisted recording (TAR) disk a heat sink layer may be located below the exchange bridge layer and the SUL may be optional.Type: GrantFiled: October 18, 2010Date of Patent: September 24, 2013Assignee: HGST Netherlands B.V.Inventors: Olav Hellwig, Dan Saylor Kercher, Ernesto E. Marinero, Manfred Ernst Schabes, Dieter K. Weller, Gabriel Zeltzer
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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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Perpendicular magnetic recording media with magnetic anisotropy gradient and local exchange coupling
Patent number: 8501330Abstract: A perpendicular magnetic recording medium adapted for high recording density and high data recording rate comprises a non-magnetic substrate having at least one surface with a layer stack formed thereon, the layer stack including a perpendicular recording layer containing a plurality of columnar-shaped magnetic grains extending perpendicularly to the substrate surface for a length, with a first end distal the surface and a second end proximal the surface, wherein each of the magnetic grains has: (1) a gradient of perpendicular magnetic anisotropy field Hk extending along its length between the first end and second ends; and (2) predetermined local exchange coupling strengths along the length.Type: GrantFiled: October 11, 2011Date of Patent: August 6, 2013Assignee: Seagate Technology LLCInventors: Shaoping Li, Kaizhong Gao, Lei Wang, Wenzhong Zhu, Xiaobin Wang -
Patent number: 8475947Abstract: A perpendicular magnetic recording medium, which includes a first magnetic recording layer, a second magnetic recording layer, and a third magnetic recording layer disposed sequentially on a nonmagnetic substrate, and a coupling layer formed between the first and second magnetic recording layers. The first, second and third magnetic recording layers have an easy axis of magnetization in a direction perpendicular to a film plane of the nonmagnetic substrate. The first and second magnetic recording layers are ferromagnetically coupled via the coupling layer.Type: GrantFiled: March 6, 2008Date of Patent: July 2, 2013Assignee: Fuji Electric Co., Ltd.Inventors: Akira Sato, Shunji Takenoiri, Yasushi Sakai
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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: 8455118Abstract: An apparatus may include a composite soft underlayer and a perpendicular magnetic recording layer overlying the composite soft underlayer. The composite soft underlayer may include a growth template layer, a negative magnetic anisotropy layer overlying the growth template layer, and a magnetically soft layer overlying the negative magnetic anisotropy layer. In some embodiments, the negative magnetic anisotropy layer includes a plurality of grains, and substantially all the grains have negative magnetic anisotropy along an axis substantially perpendicular to a major plane of the composite soft underlayer. In some embodiments, the negative magnetic anisotropy layer includes a thickness of less than or equal to about 3 nm.Type: GrantFiled: August 31, 2010Date of Patent: June 4, 2013Assignee: Seagate Technology LLCInventors: Kai-Chieh Chang, Li Tang, Shanghsien S. Rou, Connie Chunling Liu, Bogdan Florin Valcu, Wen Jiang, Tao Zhang
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Publication number: 20130070361Abstract: According to one embodiment, a magnetic medium includes at least one recording layer including a first magnetic layer, a second magnetic layer and a non-magnetic layer. The first magnetic layer is form of a first magnetic material having a first magnetic anisotropy. The second magnetic layer is made of a second magnetic material having a second magnetic anisotropy different from the first magnetic anisotropy. The non-magnetic layer is made of a non-magnetic material and between the first and second magnetic layers, the first magnetic layer and the second magnetic layer being coupled such that directions of magnetization of the first and second magnetic layers are opposed to each other.Type: ApplicationFiled: August 10, 2012Publication date: March 21, 2013Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Tao Yang, Hirofumi Suto, Tazumi Nagasawa, Kiwamu Kudo, Rie Sato, Koichi Mizushima
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Patent number: 8400735Abstract: The present invention relates to a magnetic recording medium (100). The invention finds a particularly interesting application in the field of data stored on hard disks. The medium (100) comprises an assembly of magnetic zones disposed on a substrate (102), each magnetic zone comprising at least one first (C?1) and one second (C?2) stacked magnetic layers separated from each other by a non-magnetic layer (NM?). In addition, said first magnetic layer (C?1) presents magnetization substantially oriented parallel to the plane of said substrate (102) and said second magnetic layer (C?2) presents magnetization substantially oriented perpendicular to the plane of said substrate (102).Type: GrantFiled: November 20, 2008Date of Patent: March 19, 2013Assignees: Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Centre National de la Recherche ScientifiqueInventors: Bernard Dieny, Jérôme Moritz, Bernard Rodmacq
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Publication number: 20130052486Abstract: A magnetic recording medium has both satisfactory SNRs at high frequencies and satisfactory squash resistance, and is suitable for higher density recording. The magnetic recording medium includes at least a soft magnetic underlayer and a magnetic recording layer on a non-magnetic substrate. The soft magnetic underlayer includes a first soft magnetic layer, a second soft magnetic layer, an exchange coupling control layer, a third soft magnetic layer, and a fourth soft magnetic layer stacked in this order from the non-magnetic substrate side. The first and fourth soft magnetic layers both have a characteristic frequency of relative permeability higher than a higher one of characteristic frequencies of relative permeability of the second and third soft magnetic layers, and the second and third soft magnetic layers both have a relative permeability higher than a higher one of the relative permeabilities of the first and fourth soft magnetic layers.Type: ApplicationFiled: August 8, 2012Publication date: February 28, 2013Applicant: FUJI ELECTRIC CO., LTD.Inventor: Shinji UCHIDA
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Patent number: 8367229Abstract: The present invention relates to a perpendicular magnetic recording medium including a nonmagnetic substrate, and at least a soft magnetic layer (SUL), an alignment control layer, a magnetic recording layer and a protective layer formed on the nonmagnetic substrate, wherein the magnetic recording layer is constituted of two or more layers and includes a first magnetic recording layer and a second magnetic recording layer from the nonmagnetic substrate side and, regarding magnetocrystalline anisotropic energy Ku of each magnetic recording layer, the first magnetic recording layer has 4×106 erg/cc or higher and the second magnetic recording layer has 2×106 erg/cc or lower, wherein the first magnetic recording layer is constituted of CoCrPtRu magnetic alloy crystal grains and grain boundaries made of an oxide and the area of grain boundaries is 30% or more based on the entire area in a planar TEM observation of the first magnetic recording layer.Type: GrantFiled: September 30, 2008Date of Patent: February 5, 2013Assignee: Showa Denko K.K.Inventor: Yuzo Sasaki
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Patent number: 8361640Abstract: Embodiments of the present invention provide recording area separated magnetic recording media (DTMs, BPMs) allowing magnetic heads to fly lower. According to one embodiment, the recording area separated magnetic recording media are configured so that magnetic recording layers have parts with the relatively higher element ratio of a ferromagnetic material, and parts with the lower element ratio of the ferromagnetic material, occurring periodically in the in-plane direction, and the average height from the substrate surface of the parts with the relatively higher element ratio of a ferromagnetic material is higher than the average height from the substrate surface of the parts with the lower element ratio of the ferromagnetic material.Type: GrantFiled: February 20, 2009Date of Patent: January 29, 2013Assignee: HGST Netherlands B.V.Inventors: Toshinori Ono, Hiroshi Kanai, Tatsuysa Hinoue, Hiroyuki Suzuki, Hiroshi Inaba
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Publication number: 20120320666Abstract: There is provided a magnetoresistive element whose magnetization direction is stable in a direction perpendicular to the film surface and whose magnetoresistance ratio is controlled, as well as magnetic memory using such a magnetoresistive element. By having the material of a ferromagnetic layer forming the magnetoresistive element comprise a ferromagnetic material containing at least one type of 3d transition metal, or a Heusler alloy, to control the magnetoresistance ratio, and by controlling the thickness of the ferromagnetic layer on an atomic layer level, the magnetization direction is changed from being in-plane with the film surface to being perpendicular to the film surface.Type: ApplicationFiled: February 14, 2011Publication date: December 20, 2012Applicants: Tohoku University, Hitachi, Ltd.Inventors: Hideo Ohno, Shoji Ikeda, Fumihiro Matsukura, Masaki Endoh, Shun Kanai, Katsuya Miura, Hiroyuki Yamamoto
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Publication number: 20120307395Abstract: According to one embodiment, a perpendicular magnetic recording medium includes a first granular recording layer characterized by a magnetic anisotropy Ku1, a second granular recording layer above the first granular recording layer characterized by a magnetic anisotropy Ku2, and a third granular recording layer above the second granular recording layer characterized by a magnetic anisotropy Ku3, wherein Ku3<Ku2>Ku1. In another embodiment, a magnetic medium includes a first recording layer with a first CoCrPt alloy in a first ratio X1, a second recording layer above the first recording layer and having a second CoCrPt alloy in a second ratio X2, and a third recording layer above the second recording layer having a third CoCrPt alloy in a third ratio X3 with each ratio defined as a concentration of Pt divided by a concentration of Cr in the respective CoCrPt alloy, wherein X3<X2>X1.Type: ApplicationFiled: May 31, 2011Publication date: December 6, 2012Applicant: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Shun Tonooka, Kiwamu Tanahashi, Hiroyuki Nakagawa, Ichiro Tamai
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Publication number: 20120275059Abstract: According to one embodiment, a magnetic recording medium includes a substrate, an auxiliary layer formed on the substrate, and at least one perpendicular magnetic recording layer formed on the auxiliary layer. The perpendicular magnetic recording layer includes a magnetic dot pattern. The perpendicular magnetic recording layer is made of an alloy material containing one element selected from iron and cobalt, and one element selected from platinum and palladium. This alloy material has the L10 structure, and is (001)-oriented. The auxiliary layer includes a dot-like first region covered with the magnetic dot pattern, and a second region not covered with the magnetic dot pattern. The first region is made of one metal selected from (100)-oriented nickel and (100)-oriented iron. The second region contains an oxide of the metal used in the first region.Type: ApplicationFiled: January 16, 2012Publication date: November 1, 2012Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Tomoyuki Maeda, Yousuke Isowaki, Akira Watanabe
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Publication number: 20120251846Abstract: A magnetic recording (PMR) disk structure is described. The PMR disk structure may include a magnetic capping layer being substantially free of an oxide, an upper magnetic layer with an oxide content disposed directly below and in contact with the magnetic capping layer, and an upper exchange coupling layer disposed below the upper magnetic layer.Type: ApplicationFiled: March 31, 2011Publication date: October 4, 2012Applicant: WD MEDIA, INC.Inventors: Mrugesh Desai, Kyongha Kang, Jian Zhou, B. Ramamurthy Acharya
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Patent number: 8277962Abstract: A perpendicular recording medium having a perpendicular magnetic recording layer and a magnetically soft underlayer structure disposed beneath the recording layer. The soft underlayer structure includes at least first and second soft magnetic layers having different magnetic permeabilities to create a magnetic permeability gradient in the soft underlayer structure. One or more of the soft magnetic layers can be anti-parallel coupled. The soft underlayer structure of the present invention having a magnetic permeability gradient advantageously leads to reduced adjacent track erasure (ATE) while maintaining good overwrite (OW) properties.Type: GrantFiled: September 10, 2010Date of Patent: October 2, 2012Assignee: Seagate Technology LLCInventors: Jianing Zhou, B. Ramamurthy Acharya, E. Noel Abarra, Gunn Choe
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Patent number: 8279739Abstract: A heat-assisted magnetic recording medium that includes a substrate, underlayers formed on the substrate, and a magnetic layer which is formed on the underlayers and contains either an FePt alloy having an L10 structure or a CoPt alloy having an L10 structure as a main component, wherein the underlayers include a first underlayer formed from an amorphous alloy, a second underlayer formed from an alloy having a BCC structure containing Cr as a main component and also containing at least one element selected from among Ti, Mo, W, V, Mn and Ru, and a third underlayer formed from MgO. Also, a magnetic storage device that uses the heat-assisted magnetic recording medium.Type: GrantFiled: August 19, 2010Date of Patent: October 2, 2012Assignee: Showa Denko K.K.Inventors: Tetsuya Kanbe, Yuzo Sasaki, Atsushi Hashimoto
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Publication number: 20120236633Abstract: According to one embodiment, a magnetic recording element includes a stacked body. The stacked body includes a first and a second stacked unit. The first stacked unit includes first and second ferromagnetic layers and a first nonmagnetic layer. The first nonmagnetic layer is provided between the first and second ferromagnetic layers. The second stacked unit is stacked with the first stacked unit and includes third and fourth ferromagnetic layers and a second nonmagnetic layer. The fourth ferromagnetic layer is stacked with the third ferromagnetic layer. The second nonmagnetic layer is provided between the third and fourth ferromagnetic layers. An outer edge of the fourth ferromagnetic layer includes a portion outside an outer edge of the first stacked unit in a plane. A magnetization direction of the second ferromagnetic layer is determined by causing a spin-polarized electron and a rotating magnetic field to act on the second ferromagnetic layer.Type: ApplicationFiled: September 8, 2011Publication date: September 20, 2012Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Daisuke SAIDA, Minoru AMANO, Junichi ITO, Yuichi OHSAWA, Saori KASHIWADA, Chikayoshi KAMATA, Tadaomi DAIBOU
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Patent number: 8270286Abstract: Disclosed is a thermally assisted magnetic recording medium comprising a substrate, a plurality of underlayers formed on the substrate, and a magnetic layer which is formed on the underlayers and predominantly comprised of an alloy having an L10 structure, characterized in that at least one of said underlayers is predominantly comprised of MgO and comprises at least one kind of an element having a free energy for oxidation of, per mol of oxygen, not higher than ?120 kcal/mol·O2 at 1000° C. The element having the free energy for oxidation is preferably selected from Al, Si, Ti, V, Cr, Mn, Zr and B. The thermally assisted magnetic recording medium has a magnetic layer comprised of magnetic crystal grains with uniform diameters, and exhibiting a sufficiently weak exchange coupling between magnetic grains.Type: GrantFiled: March 28, 2011Date of Patent: September 18, 2012Assignee: Showa Denko K.K.Inventors: Tetsuya Kanbe, Atsushi Hashimoto, Takayuki Fukushima
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Patent number: 8263239Abstract: A laminated magnetic recording structure for use in perpendicular or longitudinal recording is described. A small amount of ferromagnetic coupling is added between the two magnetic layers that are sufficiently decoupled to switch independently. In one embodiment the coupling is achieved by doping the spacer layer with a ferromagnetic material. Ruthenium (Ru), which is a preferred nonmagnetic material for spacer layers with cobalt (Co) being the preferred magnetic material. The weak ferromagnetic coupling can also be achieved through the use of platinum, palladium and alloys thereof for the spacer layer without the addition of a ferromagnetic element, but alternatively they can also be doped with ferromagnetic elements. For embodiments for perpendicular recording the spacer layer further can additionally comprise oxides of one or more elements selected from the group consisting of Si, Ta, Ti, Nb, Cr, V and B.Type: GrantFiled: June 26, 2006Date of Patent: September 11, 2012Assignee: HGST Netherlands B.V.Inventors: Andreas Klaus Berger, Hoa Van Do, Eric Edward Fullerton, David Thomas Margulies, Natacha Frederique Supper
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Patent number: 8257845Abstract: Embodiments of the present invention help to produce discrete track media and bit patterned media having both excellent recording and reproducing performance and reliability. According to one embodiment, a manufacturing method forms a nonmagnetic layer mainly composed of the same element as a nonmagnetic element contained in magnetic recording layers and on the magnetic recording layers and a mask layer having apertures for forming more concentrated parts of the nonmagnetic element in the magnetic recording layers on the nonmagnetic layer. The method implants ions of the nonmagnetic element through the nonmagnetic layer masked by the mask layer to form the more concentrated parts of the nonmagnetic element in the magnetic recording layer.Type: GrantFiled: February 10, 2009Date of Patent: September 4, 2012Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Tatsuya Hinoue, Hiroshi Kanai, Toshinori Ono, Hiroyuki Suzuki, Hiroshi Inaba
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Publication number: 20120219827Abstract: A stack including a crystallographic orientation interlayer, a magnetic zero layer disposed on the interlayer, and a magnetic recording layer disposed on the magnetic zero layer is disclosed. The magnetic zero layer is non-magnetic or has a saturation magnetic flux density (Bs) less than about 100 emu/cc. The magnetic zero layer and the magnetic layer include grains surrounded by a non-magnetic segregant. The magnetic zero layer provides a coherent interface between the interlayer and the magnetic layer with a lattice mismatch less than about 4%.Type: ApplicationFiled: February 28, 2011Publication date: August 30, 2012Applicant: SEAGATE TECHNOLOGY LLCInventors: Jai-Young Kim, Thomas P. Nolan, Kyongha Kang, Shoutao Wang, Vincent D. Nguyen, Abebe Hailu, Charles C. Chen
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Patent number: 8252367Abstract: Soft magnetic film fabricated with preferred uniaxial anisotropy for perpendicular recording. One type of cathode design has a field direction that is parallel to the direction of the Hex of the second SUL with a magnetically-pinned first SUL. In addition, SUL structures having low AP exchange energy also are disclosed. The SUL structure combines the cathode field direction of the SUL2 with the pinned SUL1. The SUL1 is magnetically pinned to the pinning layer and the pinning direction is parallel to the direction of the cathode field applied during deposition of the SUL1. High Hc ferro-magnetic materials may be deposited onto a heated substrate that is magnetized along the radial direction by the cathode field. The pinning field may be higher than the cathode field, indicating that the cathode field during deposition of the SUL2 cannot disturb the magnetic state of the SUL1 pinned to pinning layer.Type: GrantFiled: December 19, 2007Date of Patent: August 28, 2012Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Gunn Choe, Yoshihiro Ikeda, Masayoshi Shimizu, Kiwamu Tanahashi
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Patent number: 8247094Abstract: The present invention relates to a perpendicular magnetic recording medium including a nonmagnetic substrate, and at least a soft magnetic layer (SUL), an alignment control layer, a magnetic recording layer and a protective layer formed on the nonmagnetic substrate; wherein the magnetic recording layer is constituted of three or more layers and includes a first magnetic recording layer, a second magnetic recording layer and a third magnetic recording layer from the substrate side, and also includes an exchange coupling reduction layer for reducing exchange coupling of both layers between the second magnetic recording layer and the third magnetic recording layer and, regarding magnetocrystalline anisotropic energy Ku of each magnetic recording layer, the first magnetic recording layer has 4×106 erg/cc or higher, the second magnetic recording layer has 2×106 erg/cc or lower and the third magnetic recording layer has 1×106 erg/cc or lower.Type: GrantFiled: October 2, 2008Date of Patent: August 21, 2012Assignee: Showa Denko K.K.Inventor: Yuzo Sasaki
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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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Publication number: 20120189872Abstract: A perpendicular magnetic disk is provided. The disk includes, on a base and in the order from bottom, a first granular magnetic layer group including a plurality of magnetic layers each having a granular structure, a non-magnetic layer having Ru or a Ru alloy as a main component, a second granular magnetic layer group including a plurality of magnetic layers each having the granular structure, and an auxiliary recording layer having a CoCrPtRu alloy as a main component. Layers closer to a front surface among the plurality of magnetic layers included in the first granular magnetic layer group having an equal or smaller content of Pt. Layers closer to the front surface among the plurality of magnetic layers included in the second granular magnetic layer group having an equal or smaller content of Pt and having an equal or larger content of an oxide.Type: ApplicationFiled: May 20, 2011Publication date: July 26, 2012Applicant: WD MEDIA (SINGAPORE) PTE. LTD.Inventors: Teiichiro Umezawa, Takenori Kajiwara, Tokichiro Sato
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Patent number: 8211557Abstract: A magnetic microstructure comprising (i) a magnetic storage layer having a magnetic easy axis perpendicular to a film plane of the storage magnetic layer; (ii) a magnetic assist layer having a magnetic easy axis in the film plane; and (iii) a phase transition interlayer between the magnetic storage layer and the magnetic assist layer. The phase transition layer comprises a material, such as FeRh, that switches from antiferromagnetic at ambient to ferromagnetic at a transition temperature that is greater than ambient, but below the Curie temperature. When the phase transition interlayer is in antiferromagnetic phase, there exists little magnetic coupling between the storage and assist layers. When the interlayer changes to ferromagnetic phase, the interlayer couples the magnetic moments of the storage and assist layer ferromagnetically.Type: GrantFiled: January 31, 2007Date of Patent: July 3, 2012Assignee: Carnegie Mellon UniversityInventors: Jian-Gang Zhu, David E. Laughlin
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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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Publication number: 20120141833Abstract: [Problem] A perpendicular magnetic disk with an improved SNR and an increased recording density by further improving crystal orientation of a preliminary ground layer formed of an Ni-base alloy is provided. [Solution] A typical structure of the perpendicular magnetic disk according to the present invention includes, on a base 110, a soft magnetic layer 130, a Ta alloy layer 140 provided on the soft magnetic layer 130, an Ni alloy layer 142 provided on the Ta alloy layer 140, a ground layer 150 provided on the Ni alloy layer 142 and having Ru as a main component, and a granular magnetic layer 160 provided on the ground layer 150. The Ta alloy layer 140 is a layer containing 10 atomic percent or more and 45 atomic percent or less Ta and having amorphous and soft magnetic properties.Type: ApplicationFiled: May 31, 2011Publication date: June 7, 2012Applicant: WD MEDIA (SINGAPORE) PTE. LTD.Inventors: TEIICHIRO UMEZAWA, KAZUAKI SAKAMOTO
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Publication number: 20120135275Abstract: A magnetic memory includes: a magnetization fixed layer having perpendicular magnetic anisotropy, a magnetization direction of the magnetization fixed layer being fixed; an interlayer dielectric; an underlayer formed on upper faces of the magnetization fixed layer and the interlayer dielectric; and a data recording layer formed on an upper face of the underlayer and having perpendicular magnetic anisotropy. The underlayer includes: a first magnetic underlayer; and a non-magnetic underlayer formed on the first magnetic underlayer. The first magnetic underlayer is formed with such a thickness that the first magnetic underlayer does not exhibit in-plane magnetic anisotropy in a portion of the first magnetic underlayer formed on the interlayer dielectric.Type: ApplicationFiled: November 23, 2011Publication date: May 31, 2012Applicant: Renesas Electronics CorporationInventors: Eiji Kariyada, Katsumi Suemitsu, Hironobu Tanigawa, Kaoru Mori, Tetsuhiro Suzuki, Kiyokazu Nagahara, Yasuaki Ozaki, Norikazu Ohshima
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Publication number: 20120135273Abstract: A STT-RAM MTJ is disclosed with a MgO tunnel barrier formed by natural oxidation process. A Co10Fe70B20/NCC/Co10Fe70B20, Co10Fe70B20/NCC/Co10Fe70B20/NCC, or Co10Fe70B20/NCC/Co10Fe70B20/NCC/Co10Fe70B20 free layer configuration where NCC is a nanocurrent channel layer made of Fe(20%)-SiO2 is used to minimize Jc0 while enabling higher thermal stability, write voltage, read voltage, Ho, and Hc values that satisfy 64 Mb design requirements. The NCC layer is about 10 Angstroms thick to match the minimum Fe(Si) grain diameter size. The MTJ is annealed with a temperature of about 330° C. to maintain a high magnetoresistive ratio while maximizing Hk?(interfacial) for the free layer thereby reducing Heff and lowering the switching current. The Co10Fe70B20 layers are sputter deposited with a low pressure process with a power of about 15 Watts and an Ar flow rate of 40 standard cubic centimeters per minute to lower Heff for the free layer.Type: ApplicationFiled: November 30, 2010Publication date: May 31, 2012Inventors: Cheng T. Horng, Ru-Ying Tong, Guenole Jan
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Publication number: 20120135274Abstract: A magnetic film or layer includes a non-hexagonal close pack (non-hcp) structure.Type: ApplicationFiled: November 30, 2010Publication date: May 31, 2012Inventors: CHUN WANG, Connie Liu, Xiaoding Ma, Li Tang, Kueir-Weei Chour
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Publication number: 20120127609Abstract: A structure for high performance perpendicular magnetic recording media has a substrate with a plurality of sequential layers including an adhesion layer, a first soft underlayer (SUL), a coupling layer, a second SUL, a seed layer, a Ru layer, and an onset layer; at least one oxide layer on the onset layer and having a composition with graded anisotropy to improve overwrite of the media; an exchange coupling layer (ECL) on the at least one oxide layer; a cap layer; a decoupling-controlled layer between the ECL and the cap layer to reduce lateral exchange coupling in the cap layer on the ECL; and a carbon overcoat on the cap layer.Type: ApplicationFiled: November 18, 2010Publication date: May 24, 2012Applicant: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Jack J. Chang, Zhupei Shi
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Patent number: 8163405Abstract: Multiple anisotropy layered magnetic structures for controlling reversal mechanism and tightening of switching field distribution in bit patterned media are disclosed. The invention extends the exchange spring concept to more variable and sophisticated structures. Three or more layers with different anisotropy or anisotropy gradients increase writeability gains beyond the simple hard/soft bilayer exchange spring concept for BPM. The structures have a thin very hard, high anisotropy center layer that acts as a threshold or pinning layer for domain wall propagation through the entire media structure. In addition or alternatively, a thin very soft, low anisotropy center layer in between the commonly used soft surface layer and hard media layer allows quick initial propagation of the domain wall into the center of the media structure. Various properties of the media structures can be tuned more independently for optimization if using more advanced multi-anisotropy layer stacks.Type: GrantFiled: March 27, 2009Date of Patent: April 24, 2012Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Thomas Hauet, Olav Hellwig, Manfred Ernst Schabes
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Patent number: 8147996Abstract: 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: June 7, 2005Date of Patent: April 3, 2012Assignee: Seagate Technology LLCInventors: Qixu Chen, Charles Frederick Brucker, Chung-Hee Chang, Thomas Patrick Nolan, Samuel Dacke Harkness, IV
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Publication number: 20120064375Abstract: A method for manufacturing a magnetic media for perpendicular magnetic data recording. The method includes depositing a Ru layer in a pure oxygen atmosphere and then further depositing Ru in the presence of oxygen to form a thin pseudo onset layer. The pseudo onset layer can advantageously be depositing in the same deposition chamber and using the same target as that used to deposit the underlying Ru layer. This saves a great deal of manufacturing cost and complexity. The presence of the pseudo onset layer reduces grains size and increases grain separation in a high Ku magnetic layer deposited thereon, thereby increasing signal to noise ratio and decreasing magnetic core width (MCW).Type: ApplicationFiled: September 14, 2010Publication date: March 15, 2012Applicant: Hitachi Global Storage Technologies Netherlands B. V.Inventors: Gunn Choe, Yoshihiro Ikeda
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Patent number: 8119264Abstract: A perpendicular magnetic recording disk has a granular cobalt alloy recording layer (RL) containing an additive oxide or oxides, an intermediate layer (IL) as an exchange-break layer on the “soft” magnetic underlayer (SUL), and an ultrathin nucleation film (NF) between the IL and the RL. In the method of making the disk, the IL is deposited at a relatively low sputtering pressure, to thereby reduce the roughness of the RL and overcoat (OC), while the NF and RL are deposited at substantially higher sputtering pressures. The resulting disk has good recording properties and improved corrosion resistance over a comparable disk made with an IL deposited at high sputtering pressure and without the NF. The NF may be a discontinuous film with an average thickness of less than about 1 nm.Type: GrantFiled: March 24, 2010Date of Patent: February 21, 2012Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventor: Ernesto E. Marinero
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Patent number: 8076013Abstract: A magnetic recording medium (10) has a substrate (12) and a perpendicular magnetic recording layer (30) formed over the substrate (12). The perpendicular magnetic recording layer (30) has a granular layer (20) in which a magnetic signal is recorded and a continuous film layer (24) magnetically coupled to the granular layer (20). The continuous film layer (24) has hard magnetic portions (204) formed in positions corresponding to the recording regions where magnetic signals are recorded in the granular layer (20) and magnetic shield portions (202) formed between the hard magnetic portions (204), each having a magnetization curve whose slope is larger than those of the hard magnetic portions in the region where the applied magnetic filed is zero when the magnetization curve is measured, and each having a residual magnetic polarization smaller than those in the hard magnetic portions.Type: GrantFiled: February 13, 2008Date of Patent: December 13, 2011Assignee: WD Media (Singapore) Pte. Ltd.Inventors: Yoshiaki Sonobe, Takahiro Onoue, Koichi Wago
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Perpendicular magnetic recording media with magnetic anisotropy gradient and local exchange coupling
Patent number: 8048545Abstract: A perpendicular magnetic recording medium adapted for high recording density and high data recording rate comprises a non-magnetic substrate having at least one surface with a layer stack formed thereon, the layer stack including a perpendicular recording layer containing a plurality of columnar-shaped magnetic grains extending perpendicularly to the substrate surface for a length, with a first end distal the surface and a second end proximal the surface, wherein each of the magnetic grains has: (1) a gradient of perpendicular magnetic anisotropy field Hk extending along its length between the first end and second ends; and (2) predetermined local exchange coupling strengths along the length.Type: GrantFiled: December 7, 2010Date of Patent: November 1, 2011Assignee: Seagate Technology LLCInventors: Shaoping Li, Kaizhong Gao, Lei Wang, Wenzhong Zhu, Xiaobin Wang -
Patent number: 8036070Abstract: A magnetic recording device comprising at least one unstructured recording support exhibiting at least one elementary magnetic layer, the recording support having a magnetization perpendicular to the plane of the support characterized in that it comprises magnetic elements having a magnetization perpendicular to the plane of the support and a greater inversion field than the inversion field of the recording support, and which are separated from the recording support by a decoupling layer made of a nonmagnetic material so that the magnetic elements produce a dipolar field in the recording support. The magnetic elements are spaced apart from one another by nonmagnetic regions, each magnetic element defining during a write operation a memory point in the recording support.Type: GrantFiled: November 10, 2008Date of Patent: October 11, 2011Assignee: Centre National de la Recherche ScientifiqueInventors: Gilles Louis Gaudin, Pierre-Jean Zermatten, Ioan Mihai Miron, Alain Schuhl
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Patent number: 8021770Abstract: A perpendicular type of magnetic recording medium includes a substrate, a soft magnetic underlying section including a plurality of distinct layers soft magnetic material, a recording section, and an intermediate section upon which the recording section is formed. The intermediate section is provided to improve the crystal orientation and impart a desired magnetic characteristic to the recording section. An uppermost one of the layers of soft magnetic material which, of all of the layers of soft magnetic material, is disposed closest to the intermediate section is predisposed to induce the intermediate section to crystallize in a desired way as it is formed. Therefore, the intermediate section may have a minimal thickness and yet achieve a crystallization that is sufficient to control the forming of the recording section.Type: GrantFiled: March 12, 2010Date of Patent: September 20, 2011Assignee: Samsung Electronics Co., Ltd.Inventors: Sok-hyun Kong, Hoo-san Lee, Sadayuki Watanabe, Shunji Takenoiri
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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: 7989097Abstract: According to one embodiment, a magnetic recording medium includes a substrate, a first underlayer formed on the substrate and including an amorphous alloy containing Ni, a crystalline second underlayer formed on the first underlayer and including simple Cr or an alloy containing Cr, and a magnetic recording layer formed on the second underlayer and including at least one element of Fe and Co and at least one element of Pt and Pd, and containing magnetic crystal grains having an L10 structure. An oxygen amount remaining on the upper surface of the second underlayer is larger than an oxygen amount remaining on the lower surface of the second underlayer, and a normal line to a (001) plane of the magnetic crystal grains in the magnetic recording layer is oriented with a tilt angle in a range of 3 to 25° to a normal line to a medium plane.Type: GrantFiled: July 26, 2006Date of Patent: August 2, 2011Assignee: Kabushiki Kaisha ToshibaInventor: Tomoyuki Maeda
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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: 7955723Abstract: A perpendicular magnetic recording medium comprising a pair of soft magnetic layers that are laminated via a non-magnetic layer and antiparallel-coupled to each other and that are provided between a non-magnetic substrate and a magnetic recording layer, wherein spike noise and medium noise can be positively suppressed when information recording and reproduction are carried out at high recording surface density. At least one pair of soft magnetic layers are laid and formed via a non-magnetic layer on a substrate of a non-magnetic material so that magnetic characteristics obtained by integrating the pair of soft magnetic layers have a magnetic hysteresis to thereby prevent the formation of a magnetic domain wall.Type: GrantFiled: March 27, 2006Date of Patent: June 7, 2011Assignee: WD Media (Singapore) Pte.Ltd.Inventors: Teiichiro Umezawa, Yoshiaki Sonobe, Kong Kim