Patents by Inventor E. Noel Abarra
E. Noel Abarra has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9005781Abstract: 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 antiparallel 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 14, 2012Date of Patent: April 14, 2015Assignee: Seagate Technology LLCInventors: Jianing Zhou, B. Ramamurthy Acharya, E. Noel Abarra, Gunn Choe
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Publication number: 20130022842Abstract: 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 antiparallel 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: ApplicationFiled: September 14, 2012Publication date: January 24, 2013Applicant: SEAGATE TECHNOLOGY LLCInventors: Jianing Zhou, B. Ramamurthy Acharya, E. Noel Abarra, Gunn Choe
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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: 8110298Abstract: Perpendicular magnetic recording media having a magnetic capping layer that is exchange coupled to an underlying perpendicular magnetic recording layer. The magnetic coupling layer is a granular layer having a high saturation magnetization (Ms). The perpendicular magnetic recording layer can include magnetic grains separated by an oxide grain boundary phase.Type: GrantFiled: March 3, 2006Date of Patent: February 7, 2012Assignee: Seagate Technology LLCInventors: Gunn Choe, B. Ramamurthy Acharya, Min Zheng, E. Noel Abarra
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Patent number: 7901802Abstract: 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: March 15, 2007Date of Patent: March 8, 2011Assignee: Seagate Technology LLCInventors: Jianing Zhou, B. Ramamurthy Acharya, E. Noel Abarra, Gunn Choe
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Publication number: 20100328818Abstract: 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: ApplicationFiled: September 10, 2010Publication date: December 30, 2010Applicant: Seagate Technology LLCInventors: Jianing Zhou, B. Ramamurthy Acharya, E. Noel Abarra, Gunn Choe
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Patent number: 7796358Abstract: A system for reducing spike noise in a perpendicular recording medium having a soft underlayer is provided. The system radially biases the soft underlayer to substantially eliminate domain walls therein. In a first embodiment of the system, a permanent magnetic bias ring is disposed generally adjacent to the soft underlayer and a magnetic circuit is formed between the magnetic ring and the soft underlayer. Other embodiments include a concentric stationary magnetic flux return disk to extend the radial distance of the flux path. In alternative embodiments, a ferromagnetic spindle assembly is modified to produce a radiation pattern that has a net radial exterior field that biases the adjacent soft underlayer of the medium. The entire assembly can be shielded from external magnetic fields in the disk drive. Further, the shielding may operate as part of the magnetic circuit.Type: GrantFiled: March 2, 2006Date of Patent: September 14, 2010Assignee: Seagate Technology LLCInventors: Albert Tchekanov, Robert Weng, E. Noel Abarra, Michael Mallary
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Patent number: 7588842Abstract: A magnetic recording medium and a magnetic recording apparatus for perpendicular magnetic recording. The recording medium includes a magnetically soft underlayer and a hard magnetic pinning layer having perpendicular anisotropy. The magnetically soft underlayer is substantially free of domain walls.Type: GrantFiled: September 2, 2005Date of Patent: September 15, 2009Assignee: Maxtor CorporationInventors: E. Noel Abarra, Min Zheng, Paramjit Gill
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Patent number: 7566507Abstract: A magnetic recording medium is provided with an hcp Co alloy magnetic layer with the crystallographic c-axes tilted at an angle from a substrate surface and fixed relative to a recording direction. The tilt is induced by epitaxial growth of the hcp Co alloy on an obliquely evaporated nonmagnetic polycrystalline underlayer, so that the magnetic recording medium exhibits thermal stability and improved overwrite with a single pole-type head.Type: GrantFiled: September 7, 2005Date of Patent: July 28, 2009Assignee: Fujitsu LimitedInventors: E. Noel Abarra, Akihiro Inomata, Antony Ajan
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Patent number: 7354665Abstract: A magnetic recording medium is provided with a substrate, a recording magnetic layer made of a CoCr alloy and having a (11 20) crystallographic texture, and an underlayer, made of an AlV or AlRuV alloy, disposed between the substrate and the magnetic layer.Type: GrantFiled: February 23, 2005Date of Patent: April 8, 2008Assignee: Fujitsu LimitedInventors: Antony Ajan, E. Noel Abarra
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Publication number: 20070217074Abstract: 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: ApplicationFiled: March 15, 2007Publication date: September 20, 2007Applicant: SEAGATE TECHNOLOGY LLCInventors: Jianing Zhou, B. Ramamurthy Acharya, E. Noel Abarra, Gunn Choe
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Patent number: 7264892Abstract: A magnetic recording medium includes a substrate, a magnetic recording layer made of a Co alloy or a CoCr alloy, a seed layer disposed between the substrate and the magnetic recording layer, and an underlayer made of a binary alloy material having a B2 structure and disposed between the seed layer and the magnetic recording layer. The seed layer is made of a material comprising essentially of one of elements forming the binary alloy material of the underlayer.Type: GrantFiled: September 8, 2004Date of Patent: September 4, 2007Assignee: Fujitsu LimitedInventors: Antony Ajan, Akihiro Inomata, E. Noel Abarra, B. Ramamurthy Acharya
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Patent number: 6893735Abstract: A magnetic recording medium includes a nonmagnetic underlayer, an initial magnetic layer, a nonmagnetic spacer layer provided on the initial magnetic layer, and a final magnetic layer provided on the nonmagnetic spacer layer. The initial magnetic layer is disposed closer to the nonmagnetic underlayer than the final magnetic layer, and the initial and final magnetic layers are made of mutually different compositions and are anti-ferromagnetically coupled.Type: GrantFiled: May 22, 2003Date of Patent: May 17, 2005Assignee: Fujitsu LimitedInventors: B. Ramamurthy Acharya, E. Noel Abarra
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Patent number: 6828047Abstract: A magnetic recording medium is constructed to include a substrate, a magnetic layer made of a Co or Co-based alloy, and an underlayer disposed between the substrate and the magnetic layer. The underlayer is made of an ordered intermetallic material of FCC L12 or FCT L10 crystalline structure, so that c-axis of the magnetic layer is aligned in a predetermined direction.Type: GrantFiled: March 27, 2003Date of Patent: December 7, 2004Assignee: Fujitsu LimitedInventors: E. Noel Abarra, Iwao Okamoto
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Patent number: 6821652Abstract: A magnetic recording medium is constructed to include at least one exchange layer structure, and a magnetic layer formed on the exchange layer structure, where the exchange layer structure comprises a ferromagnetic layer, and a non-magnetic coupling layer provided on the ferromagnetic layer and under the magnetic layer. The ferromagnetic layer and the magnetic layer have antiparallel magnetizations. The non-magnetic coupling layer is made of a Ru-M3 alloy, where M3 is an added element or alloy, and a lattice mismatch between the non-magnetic coupling layer and the magnetic layer and the ferromagnetic layer respectively disposed above and below the non-magnetic coupling layer is adjusted to approximately 6% or less by addition of M3.Type: GrantFiled: June 6, 2000Date of Patent: November 23, 2004Assignee: Fujitsu LimitedInventors: Iwao Okamoto, E. Noel Abarra, Yoshifumi Mizoshita
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Patent number: 6773833Abstract: A magnetic storage medium includes first and second magnetic layers provided on a support substrate such that the first and second magnetic layers have respective first and second magnetizations in an anti-parallel relationship in a state no substantial writing magnetic field is applied. The first and second magnetizations are changed to a parallel relationship when a writing magnetic field is applied to the magnetic storage medium, and the first and second magnetizations are changed to the anti-parallel relationship as a result of a magnetic reversal caused in the second magnetic layer with diminishing of the writing magnetic field. The reversal is caused as a result of the action of a reversing magnetic field that dominates before the writing magnetic field is diminished and becomes zero.Type: GrantFiled: March 15, 2001Date of Patent: August 10, 2004Assignee: Fujitsu LimitedInventors: Akihiro Inomata, E. Noel Abarra, B. Ramamurthy Acharya
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Patent number: 6753101Abstract: A magnetic recording medium is provided with at least one exchange layer structure, and a magnetic layer formed on the exchange layer structure. The exchange layer structure includes a ferromagnetic layer and a non-magnetic coupling layer provided on the ferromagnetic layer and under the magnetic layer.Type: GrantFiled: June 6, 2000Date of Patent: June 22, 2004Assignee: Fujitsu LimitedInventors: E. Noel Abarra, Iwao Okamoto, Yoshifumi Mizoshita, Yuki Yoshida
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Patent number: 6689495Abstract: A magnetic recording medium is constructed to include at least one exchange layer structure and a magnetic layer provided on the exchange layer structure. The exchange layer structure includes a ferromagnetic layer and a non-magnetic coupling layer provided on the ferromagnetic layer. At least one of the ferromagnetic layer and the magnetic layer has a granular layer structure in which ferromagnetic crystal grains are uniformly distributed within a non-magnetic base material.Type: GrantFiled: June 6, 2000Date of Patent: February 10, 2004Assignee: Fujitsu LimitedInventors: Hisateru Sato, Isatake Kaitsu, E. Noel Abarra, Iwao Okamoto, Yoshifumi Mizoshita
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Publication number: 20040013910Abstract: A magnetic recording medium includes a nonmagnetic underlayer, an initial magnetic layer, a nonmagnetic spacer layer provided on the initial magnetic layer, and a final magnetic layer provided on the nonmagnetic spacer layer. The initial magnetic layer is disposed closer to the nonmagnetic underlayer than the final magnetic layer, and the initial and final magnetic layers are made of mutually different compositions and are anti-ferromagnetically coupled.Type: ApplicationFiled: May 22, 2003Publication date: January 22, 2004Applicant: Fujitsu LimitedInventors: B. Ramamurthy Acharya, E. Noel Abarra
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Patent number: 6645646Abstract: A magnetic recording medium is constructed to include at least one exchange layer structure and a magnetic layer provided on the exchange layer structure, where the exchange layer structure includes a ferromagnetic layer and a non-magnetic coupling layer provided on the ferromagnetic layer, and a magnetic bonding layer provided between the ferromagnetic layer and the non-magnetic coupling layer and/or between the non-magnetic coupling layer and the magnetic layer, wherein the magnetic bonding layer has a magnetization direction parallel to the ferromagnetic layer and the magnetic layer.Type: GrantFiled: June 6, 2000Date of Patent: November 11, 2003Assignee: Fujitsu LimitedInventors: Hisashi Umeda, E. Noel Abarra, Iwao Okamoto, Yoshifumi Mizoshita