Plural Separate Coils Patents (Class 360/123.11)
  • Patent number: 9640204
    Abstract: Implementations disclosed herein provide an apparatus comprising a write pole, and a two-layer front shield formed on the write pole, the front shield comprising, a first dielectric material formed on the first layer of the front shield, an active shield control (ASC) device formed between the two layers of the front shield on the first dielectric material configured to synchronize the response to a magnetomotive force (MMF) of a write pole and the front shield, and a second dielectric material formed on the ASC device, wherein the second layer of the front shield is formed only on top of the second dielectric material and the first layer of the front shield.
    Type: Grant
    Filed: October 31, 2016
    Date of Patent: May 2, 2017
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Xiaohong Zhang, Wei Tian, Zhe Shen, Dong Lin, Joseph Mundenar
  • Patent number: 9620153
    Abstract: A magnetic head includes a coil, a main pole, a write shield and first and second yokes. The first and second yokes are connected to the write shield. The coil includes a main coil portion for driving the main pole, a first sub-coil portion for driving the first yoke, and a second sub-coil portion for driving the second yoke. A magnetic field produced in the main pole by the main coil portion and a magnetic field produced in each of the first and second yokes by the first and second sub-coil portions are in directions opposite to each other.
    Type: Grant
    Filed: April 11, 2016
    Date of Patent: April 11, 2017
    Assignee: HEADWAY TECHNOLOGIES, INC.
    Inventors: Yoshitaka Sasaki, Kazuki Sato, Hiroyuki Ito, Shigeki Tanemura, Masakazu Okada
  • Patent number: 8995085
    Abstract: An example magnetic recording apparatus includes a magnetic recording medium and a magnetic recording head. The magnetic recording head includes a first magnetic pole to apply a recording magnetic field to a magnetic recording medium, a spin torque oscillator provided parallel to the first magnetic pole, a first coil which surrounds the first magnetic pole, to magnetize the first magnetic pole, and a second coil to pass a current independently of the first coil and magnetize the first magnetic pole. A signal processor writes and reads a signal on the magnetic recording medium by using the magnetic recording head.
    Type: Grant
    Filed: February 19, 2014
    Date of Patent: March 31, 2015
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kenichiro Yamada, Hitoshi Iwasaki, Masayuki Takagishi
  • Publication number: 20140334030
    Abstract: According to one embodiment, a recording head includes a main pole, a trailing shield including a first connecting portion and a second connecting portion, and configured to form together with the main pole a first magnetic core, a leading shield including a first connecting portion connected to the main pole through a magnetic material and an end portion opposing to the end portion of the main pole through a non-magnetic material, and configured to form together with the main pole a second magnetic core, and first and second coils wound around the first and second magnetic cores, and a connection terminal configured to flow a current through the main pole, non-magnetic conductive layer, and trailing shield.
    Type: Application
    Filed: July 25, 2014
    Publication date: November 13, 2014
    Inventors: Tomoko TAGUCHI, Yusuke TOMODA
  • Patent number: 8810961
    Abstract: According to one embodiment, a recording head includes a main pole, a trailing shield including a first connecting portion and a second connecting portion, and configured to form together with the main pole a first magnetic core, a leading shield including a first connecting portion connected to the main pole through a magnetic material and an end portion opposing to the end portion of the main pole through a non-magnetic material, and configured to form together with the main pole a second magnetic core, and first and second coils wound around the first and second magnetic cores, and a connection terminal configured to flow a current through the main pole, non-magnetic conductive layer, and trailing shield.
    Type: Grant
    Filed: July 13, 2012
    Date of Patent: August 19, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomoko Taguchi, Yusuke Tomoda
  • Patent number: 8797684
    Abstract: A method and system provide a magnetic transducer having an air-bearing surface (ABS). The magnetic transducer includes a write pole and a coil. The write pole has a pole tip and a yoke. The coil energizes the write pole and includes a plurality of turns. A turn of the plurality of turns has a first portion and a second portion. The first portion has a first length in a stripe height direction substantially perpendicular to the ABS. The second portion has a second length in the stripe height direction. The second length is greater than the first length and extends at least to at least one adjacent turn.
    Type: Grant
    Filed: December 20, 2011
    Date of Patent: August 5, 2014
    Assignee: Western Digital (Fremont), LLC
    Inventors: Ut Tran, Zhigang Bai, Kevin K. Lin
  • Patent number: 8767346
    Abstract: A magnetic recording head includes a first magnetic pole, a second magnetic pole, a spin torque oscillator, a first coil, a second coil, and a third coil. The first magnetic pole applies a recording magnetic field to a magnetic recording medium. The second magnetic pole is provided parallel to the first magnetic pole. At least a portion of the spin torque oscillator is provided between the first magnetic pole and the second magnetic pole. The first coil magnetizes the first magnetic pole. A current is passed through the second coil independently of the first coil. A current is passed through the third coil independently of both the first coil and the second coil.
    Type: Grant
    Filed: November 30, 2009
    Date of Patent: July 1, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kenichiro Yamada, Hitoshi Iwasaki, Masayuki Takagishi
  • Patent number: 8582239
    Abstract: A microwave assisted magnetic head includes a main magnetic pole; a trailing shield, a main coil for causing the main magnetic pole to generate a perpendicular recording field, at least one secondary coil for generating an in-plane alternate-current (AC) magnetic field with a frequency in a microwave band from a magnetic recording gap between the main magnetic pole and the trailing shield, nonmagnetic films formed on magnetic recording gap facing surfaces that are defined by the main magnetic pole and the trailing shield, the main magnetic pole and the trailing shield being configured with first soft magnetic films, and second soft magnetic films formed further on the surfaces of the nonmagnetic films. The second soft magnetic films have larger anisotropy fields than the first soft magnetic films have.
    Type: Grant
    Filed: June 20, 2012
    Date of Patent: November 12, 2013
    Assignee: TDK Corporation
    Inventors: Yoshikazu Soeno, Kei Hirata, Tsutomu Aoyama, Isamu Sato
  • Patent number: 8547659
    Abstract: A method and system for providing a magnetic recording head is described. The magnetic recording head has an air-bearing surface (ABS) configured to reside in proximity to a media during use. The head includes a first coil, a second coil, a main pole, and a third coil. The first coil has a first plurality of turns and is configured to carry a first write current in a first direction. The second coil has a second plurality of turns and is configured to carry a second write current in a second direction. The main pole is between the first coil and the second coil. The third coil has a third plurality of turns configured to carry a third write current in a third direction.
    Type: Grant
    Filed: May 9, 2011
    Date of Patent: October 1, 2013
    Assignee: Western Digital (Fremont), LLC
    Inventors: Zhigang Bai, Zhanjie Li, Sharat Batra
  • Patent number: 8437102
    Abstract: Embodiments in accordance with the present invention provide a magnetic head having a narrow track width and excellent in productivity for the purpose of realizing a disk storage unit having a large capacity. In a magnetic head having a plurality of flairs on a main magnetic pole, a side shield is formed via a non-magnetic film on both sides of the flair disposed close to an air bearing surface in such a fashion as to be aligned with the flair.
    Type: Grant
    Filed: October 31, 2006
    Date of Patent: May 7, 2013
    Assignee: HGST Netherlands B.V.
    Inventors: Yoji Maruyama, Takayuki Iwakura, Ichiro Ohdake, Masafumi Mochizuku
  • Patent number: 8422166
    Abstract: A magnetic head includes a coil, a main pole, a write shield, and a return path section. The return path section is located forward of the main pole in a direction of travel of a recording medium to thereby define a space. The coil includes a first coil element and second coil elements extending to pass through the space. The second coil elements are located forward of the first coil element in the direction of travel of the recording medium. The return path section includes a first portion located such that the first coil element is interposed between the first portion and the medium facing surface, and a second portion located such that the second coil elements are interposed between the second portion and the medium facing surface.
    Type: Grant
    Filed: August 9, 2012
    Date of Patent: April 16, 2013
    Assignees: Headway Technologies, Inc., Sae Magnetics (H.K.) Ltd.
    Inventors: Yoshitaka Sasaki, Hiroyuki Ito, Kazuki Sato, Shigeki Tanemura, Hironori Araki, Tatsuya Shimizu
  • Patent number: 8411390
    Abstract: A structure for providing two write assist components for perpendicular thin film heads writing to high coercivity media is disclosed. The two components provided by the present invention include a media writing assist component and a head switching assist component. The structure includes an auxiliary half coil surrounding the pole tip at the ABS, and includes conductive elements running parallel to the pole layer which are connected to the auxiliary half coil. Integrated heat sinks located at either the ABS or at a recessed position are provided. The conductive elements can prove either symmetric or asymmetric current feed geometries, which allow differential or common mode current flow to the half coil.
    Type: Grant
    Filed: October 16, 2009
    Date of Patent: April 2, 2013
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Luiz M. Franca-Neto, Bernhard E. Knigge, Petrus Antonius Van Der Heijden
  • Patent number: 8373945
    Abstract: A method and system for providing a magnetic transducer are described. The magnetic transducer includes a first pole, a write gap, a second pole, a first coil, and a second coil. The first pole has a front portion on which at least a portion of the write gap resides. The second pole includes a split yoke that includes a first portion and a second portion. At least a portion of the first coil resides between the first portion of the split yoke and the first pole. At least a portion of the second coil resides between the second portion of the split yoke and the first pole.
    Type: Grant
    Filed: April 23, 2007
    Date of Patent: February 12, 2013
    Assignee: Western Digital (Fremont), LLC
    Inventors: Peng Luo, Zhigang Bai, Yugang Wang, Kroum S. Stoev, Francis H. Liu
  • Patent number: 8363346
    Abstract: According to one embodiment, a magnetic head for perpendicular recording includes a first magnetic core includes a main pole configured to produce a recording magnetic field, and a return pole configured to reflux magnetic flux from the main pole to form a magnetic circuit in conjunction with the main pole, a first coil configured to excite magnetic flux in the magnetic circuit, side shields arranged individually on opposite sides of the main pole transversely relative to a track so as to be magnetically separated from the main pole and formed integrally with the return pole, a second magnetic core configured to form a physically closed magnetic path, a part of which comprises the return pole, and a second coil wound around the second magnetic core and configured to excite magnetic flux in the closed magnetic path.
    Type: Grant
    Filed: January 4, 2011
    Date of Patent: January 29, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Tomoko Taguchi
  • Patent number: 8345382
    Abstract: A magnetic head includes a coil, a main pole, a gap part, a write shield, and a return path section. The return path section includes a yoke part with a first coupling layer connected to the write shield and a second coupling layer magnetically coupling the first coupling layer to the yoke part. The second coupling layer has an end face facing toward a medium facing surface and located away from the medium facing surface. The coil includes i) a first coil element disposed with the first coupling layer interposed between the medium facing surface and the first coil element and ii) a plurality of second coil elements aligned perpendicularly to the medium facing surface and disposed with the second coupling layer interposed between the medium facing surface and the second coil elements. The first coil element being interposed between the main pole and the second coil elements.
    Type: Grant
    Filed: June 9, 2011
    Date of Patent: January 1, 2013
    Assignees: Headway Technologies, Inc., SAE Magnetics (H.K.) Ltd.
    Inventors: Yoshitaka Sasaki, Hiroyuki Ito, Kazuki Sato, Atsushi Iijima
  • Patent number: 8300357
    Abstract: A magnetic head includes first and second coils, a main pole, a first shield, and first and second return path sections. The first shield and the first return path section are located forward of the main pole in the direction of travel of the recording medium. The first return path section connects the main pole and the first shield so that a first space is defined. The second return path section is located backward of the main pole in the direction of travel of the recording medium so that a second space is defined. The first coil includes at least one first coil element passing through the first space. The second coil includes a plurality of second coil elements passing through the second space. The at least one first coil element is smaller in number than the second coil elements.
    Type: Grant
    Filed: December 2, 2011
    Date of Patent: October 30, 2012
    Assignees: Headway Technologies, Inc., Sae Magnetics (H.K.) Ltd.
    Inventors: Yoshitaka Sasaki, Hiroyuki Ito, Kazuki Sato, Shigeki Tanemura, Hironori Araki, Atsushi Iijima
  • Patent number: 8274757
    Abstract: According to one embodiment, a recording head includes a main pole, a trailing core, a first coil wound around the trailing core, a leading core, and a second coil wound around the leading core. The trailing core includes a return pole opposed to a trailing side of the main pole with a write gap therebetween, and side shields arranged individually on opposite sides of the main pole transversely relative to tracks and magnetically separated from the main pole at a distance not more than double a track pitch of the recording medium. The leading core includes a junction opposed to a leading side of the main pole with a gap therebetween and joined to the side shields with a width of 20 ?m or less transversely relative to the tracks and a connecting portion joined to the main pole in a position off the recording medium.
    Type: Grant
    Filed: September 2, 2011
    Date of Patent: September 25, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takuya Matsumoto, Tomoko Taguchi, Masaya Ohtake
  • Publication number: 20120229932
    Abstract: A magnetic layer for writing incorporates: a pole layer having an end face located in a medium facing surface and a lower yoke layer. A first magnetic layer for flux concentration is connected to the lower yoke layer at a location away from the medium facing surface, and passes a magnetic flux corresponding to a magnetic field generated by a first coil. A second magnetic layer for flux concentration is connected to the pole layer at a location away from the medium facing surface, and passes a magnetic flux corresponding to a magnetic field generated by a second coil. A nonmagnetic layer is disposed between the pole layer and the lower yoke layer. The lower yoke layer is connected to the pole layer at a location closer to the medium facing surface than the nonmagnetic layer.
    Type: Application
    Filed: May 21, 2012
    Publication date: September 13, 2012
    Applicants: SAE MAGNETICS (H.K.) LTD., HEADWAY TECHNOLOGIES, INC.
    Inventors: Yoshitaka Sasaki, Hiroyuki Itoh, Shigeki Tanemura, Tatsushi Shimizu, Tatsuya Shimizu
  • Patent number: 8238057
    Abstract: The present invention relates to a magnetic head and particularly to improvement of its recording element. The recording element includes a first magnetic film, a second magnetic film, a coil film, and an insulating film. The first magnetic film has a first pole portion. The second magnetic film has a second pole portion opposed to the first pole portion with a magnetic gap film therebetween and is joined to the first magnetic film at a back gap portion that is located in a rearward position with respect to a medium facing surface. The coil film extends around the back gap portion, and the insulating film encloses the coil film. Moreover, the second magnetic film entirely covers the insulating film.
    Type: Grant
    Filed: February 19, 2009
    Date of Patent: August 7, 2012
    Assignee: TDK Corporation
    Inventors: Yuji Ito, Seiji Yari
  • Publication number: 20120182644
    Abstract: According to one embodiment, a recording head includes a main pole, a trailing core, a first coil wound around the trailing core, a leading core, and a second coil wound around the leading core. The trailing core includes a return pole opposed to a trailing side of the main pole with a write gap therebetween, and side shields arranged individually on opposite sides of the main pole transversely relative to tracks and magnetically separated from the main pole at a distance not more than double a track pitch of the recording medium. The leading core includes a junction opposed to a leading side of the main pole with a gap therebetween and joined to the side shields with a width of 20 ?m or less transversely relative to the tracks and a connecting portion joined to the main pole in a position off the recording medium.
    Type: Application
    Filed: September 2, 2011
    Publication date: July 19, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Takuya MATSUMOTO, Tomoko Taguchi, Masaya Ohtake
  • Patent number: 8139319
    Abstract: A perpendicular magnetic recording system has a write head with a main perpendicular write pole connected to a yoke with first and second electrical coils. The first coil is wrapped around the yoke on one side of the main pole, and the second coil is wrapped around the yoke on the other side of the main pole. The first end of each coil is connected to a respective terminal. The second ends of the two coils are connected together and connected to a common terminal. A lead-time circuit is connected between the common terminal and the first end of one of the coils. Immediately after the direction of write current is switched by the write driver, the lead-time circuit causes the current in one of the coils to lead the current in the other coil. The current displacement between the two coils creates a precession of the magnetic flux reversal, thereby reducing the switching time of the write head.
    Type: Grant
    Filed: February 23, 2009
    Date of Patent: March 20, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V
    Inventors: John Thomas Contreras, Yimin Hsu, Manfred Ernst Schabes, Xinzhi Xing
  • Patent number: 8116031
    Abstract: A perpendicular magnetic recording system has a write head having a main helical coil (the write coil) and main pole (the write pole) that directs write flux in a direction perpendicular to the recording layer in the magnetic recording medium, and an auxiliary coil and auxiliary pole that injects magnetic flux into the write pole at an angle to the primary or perpendicular axis of the write pole. The auxiliary coil is preferably a helical coil wrapped around the auxiliary pole. The additional flux from the auxiliary pole, which is injected non-parallel to the primary magnetization of the write pole, exerts a relatively large torque on the magnetization of the write pole, thereby facilitating magnetization reversal of the write pole. Electrical circuitry is connected to the main coil and the auxiliary coil to generate the auxiliary flux simultaneous with the switching of the magnetization of the write pole.
    Type: Grant
    Filed: April 6, 2009
    Date of Patent: February 14, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Michael Alex, John Thomas Contreras, Manfred Ernst Schabes, Xinzhi Xing
  • Patent number: 8116032
    Abstract: A perpendicular magnetic recording system has a write head having a main coil (the write coil) and main pole (the write pole) that directs write flux in a direction perpendicular to the recording layer in the magnetic recording medium, and an auxiliary coil and auxiliary pole that injects magnetic flux into the write pole at an angle to the primary or perpendicular axis of the write pole. The additional flux from the auxiliary pole, which is injected non-parallel to the primary magnetization of the write pole, exerts a relatively large torque on the magnetization of the write pole, thereby facilitating magnetization reversal of the write pole. Electrical circuitry is connected to the main coil and the auxiliary coil to generate the auxiliary flux simultaneous with the switching of the magnetization of the write pole.
    Type: Grant
    Filed: April 6, 2009
    Date of Patent: February 14, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: John Thomas Contreras, Manfred Ernst Schabes, David John Seagle
  • Patent number: 8107191
    Abstract: A perpendicular magnetic recording (PMR) head is provided which records data in a PMR medium. The PMR head includes a main pole having an end portion disposed on an air bearing surface (ABS) opposed to the PMR medium and the other end portion; a return yoke spaced apart from the main pole; a sub-yoke starting from the other end portion of the main pole and extending away from the PMR medium, so as to magnetically connect the main pole with the return yoke; and a coil disposed to encircle the sub-yoke.
    Type: Grant
    Filed: December 3, 2007
    Date of Patent: January 31, 2012
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Young-hun Im, Kook-hyun Sunwoo
  • Patent number: 8102624
    Abstract: In a perpendicular magnetic recording head having a main magnetic pole layer and a return yoke layer which are laminated with a magnetic gap layer interposed therebetween on a medium-opposing surface, a pair of side coils constituting respective electrically closed circuits on a surface parallel to the medium-opposing surface are provided on both sides in a track width direction of a magnetic pole part of the main magnetic pole layer. When a leakage magnetic field spreading from the magnetic pole part of the main magnetic pole layer passes through the pair of side coils, the pair of side coils generate a demagnetizing field in such a direction as to cancel a magnetic flux change thereof, thereby preventing the leakage magnetic flux from spreading.
    Type: Grant
    Filed: May 5, 2008
    Date of Patent: January 24, 2012
    Assignee: TDK Corporation
    Inventor: Tomohiro Yamashita
  • Publication number: 20110242694
    Abstract: According to one embodiment, a magnetic head for perpendicular recording includes a first magnetic core includes a main pole configured to produce a recording magnetic field, and a return pole configured to reflux magnetic flux from the main pole to form a magnetic circuit in conjunction with the main pole, a first coil configured to excite magnetic flux in the magnetic circuit, side shields arranged individually on opposite sides of the main pole transversely relative to a track so as to be magnetically separated from the main pole and formed integrally with the return pole, a second magnetic core configured to form a physically closed magnetic path, a part of which comprises the return pole, and a second coil wound around the second magnetic core and configured to excite magnetic flux in the closed magnetic path.
    Type: Application
    Filed: January 4, 2011
    Publication date: October 6, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventor: Tomoko Taguchi
  • Publication number: 20110170216
    Abstract: A magnetic layer for writing incorporates: a pole layer having an end face located in a medium facing surface; and an upper yoke layer. A first magnetic layer for flux concentration is connected to the pole layer at a location away from the medium facing surface, and passes a magnetic flux corresponding to a magnetic field generated by a first coil. A second magnetic layer for flux concentration is connected to the upper yoke layer at a location away from the medium facing surface, and passes a magnetic flux corresponding to a magnetic field generated by a second coil. A nonmagnetic layer is disposed between the pole layer and the upper yoke layer. The upper yoke layer is connected to the pole layer at a location closer to the medium facing surface than the nonmagnetic layer.
    Type: Application
    Filed: March 18, 2011
    Publication date: July 14, 2011
    Applicants: HEADWAY TECHNOLOGIES, INC., SAE MAGNETICS (H.K.) LTD.
    Inventors: Yoshitaka SASAKI, Hiroyuki ITOH, Shigeki TANEMURA, Tatsushi SHIMIZU, Tatsuya SHIMIZU
  • Patent number: 7657992
    Abstract: A method of making a perpendicular magnetic recording (PMR) head with single or double coil layers and with a small write shield stitched onto a main write shield. The stitched shield allows the main write pole to produce a vertical write field with sharp vertical gradients that is reduced on both sides of the write pole so that adjacent track erasures are eliminated. From a fabrication point of view, both the main pole and the stitched shield are defined and formed using a single photolithographic process, a trim mask and CMP lapping process so that the main shield can be stitched onto a self-aligned main pole and stitched shield.
    Type: Grant
    Filed: December 11, 2007
    Date of Patent: February 9, 2010
    Assignee: Headway Technologies, Inc.
    Inventors: Cherng-Chyi Han, Kenichi Takano
  • Patent number: 7549216
    Abstract: The invention is directed to a method for manufacturing a thin film magnetic head comprising forming a first coil, a first pole piece and a first back gap piece on a first insulating film formed on a surface of a first magnetic film, so that the first coil, the first pole piece and the first back gap piece have a taper angle making a sectional shape wider in a lower part and narrower in an upper part; forming a second insulating film on surfaces of the first coil, the first pole piece and the first back gap piece; forming a first seed film on the second insulating film; growing a first plating film for a second coil on the first seed film in an area where the second coil is to be formed, so that the first plating film fills up spaces between the first pole piece and an outermost coil turn of the first coil, between coil turns of the first coil, and between an innermost coil turn of the first coil and the first back gap piece; and flattening the first plating film by polishing, so that to obtain a pattern of t
    Type: Grant
    Filed: March 17, 2006
    Date of Patent: June 23, 2009
    Assignees: Headway Technologies, Inc., SAE Magnetics (H.K.) Ltd.
    Inventors: Yoshitaka Sasaki, Takehiro Kamigama, Hiroyuki Itoh
  • Patent number: 7495864
    Abstract: A perpendicular magnetic recording head is provided that has a first coil layer is electrically connected to a second coil layer through contact layers. A laminator has a main magnetic pole layer and a gap layer which are formed between the first and second coil layers and above the contact layers. At both sides of the laminator, first insulating layers are formed. A second insulating layer is formed from a top surface of the laminator to top surfaces of the first insulating layers. An inclined surface is formed in each of the first insulating layers, and in the second insulating layer, the inclined surface is formed on the inclined surface of the first insulating layer.
    Type: Grant
    Filed: March 6, 2006
    Date of Patent: February 24, 2009
    Assignee: TDK Corporation Co., Ltd.
    Inventor: Kiyoshi Kobayashi
  • Publication number: 20080180838
    Abstract: A perpendicular magnetic recording (PMR) head is provided which records data in a PMR medium. The PMR head includes a main pole having an end portion disposed on an air bearing surface (ABS) that is opposite to the PMR medium; a return yoke spaced apart from the main pole; a sub-yoke starting from the other end portion and extending away from the PMR medium, so as to magnetically connect the main pole with the return yoke; and a coil disposed to enclose the sub-yoke.
    Type: Application
    Filed: December 3, 2007
    Publication date: July 31, 2008
    Applicant: SAMSUNG ELECTRONICS CO., LTD.
    Inventors: Young-hun IM, Kook-hyun SUNWOO