TAKATA,Keiji - Faculty of Engineering Science Department of Mechanical Engineering

TAKATA, Keiji

Faculty, Department/Institute

Faculty of Engineering Science Department of Mechanical Engineering

Academic status (qualification)

Professor Apr. 1,2007

Undergraduate Degrees・University

Kyushu University Faculty of Science1981

Graduate Degrees・University

Master's Degree Program 1983 Completed

Academic Degrees

Hiroshima University

Research fields	keyword
Applied physics, general

research topic	Scanning Probe Microscopy and related application techniques
Study theme state	Individual Research
research duration
Research Programs
keyword
Research field
Research Topics Overview

所属学会・団体名	役職名 (役職在任期間)
Japanese Society of Applied Physics
The Electrochemical Society of Japan

Research Publications

No.	Type of publication	Date of publication (Date of presentation)	Title	Type of research result	Jointly authored or single authored	Publisher and journal name	Volume number
1	Papers1	2017/1/22～2017,01,22,,,	In-Situ imaging of Li intercalation in graphite particles in an Li-ion battery	Academic Journal	Single-Author	Journal of Microscopy	Vol.00, Issue 0, pp1-4
2	Papers1	2016～2016,00,00,,,	Strain imaging of a LiCoO2 cathode in a Li-ion battery	Academic Journal	Co-author	THE JOURNAL OF CHEMICAL PHYSICS	145, 114201
3	International academic conference8	2016～2016,00,00,,,	High-Resolution Observation of Electronic Properties of a Cathode Material in a Lithium-Ion Battery		Co-author		EH-TuE7
4	International academic conference8	2016～2016,00,00,,,	High-Resolution Observation of Electronic Properties of an Anode Material in a Lithium-Ion Battery		Co-author		EH-WeP-17
5	International academic conference8	2016～2016,00,00,,,	Magnetic Strain Imaging of a Main Pole Tip and Upper Shield in a Hard Disk Drive		Co-author		NM-WeP-2
6	International academic conference8	2016～2016,00,00,,,	Imaging of dry-out in a LiCoO2 Cathode in a Li-ion Battery		Co-author		EH-WeP-4
7	International academic conference8	2016～2016,00,00,,,	Strain imaging of a LiCoO2 cathode in a Li-ion Battery		Co-author		EH-WeP-3
8	International academic conference8	2015～2015,00,00,,,	Magnetic Strain Imaging of a Magnetic Tape		Co-author		HKICEAS-2047
9	International academic conference8	2015～2015,00,00,,,	In-Situ High-Resolution Observation of Dryout of Electrolyte in a Lithium-Ion Battery		Co-author		HKICEAS-2049
10	International academic conference8	2015～2015,00,00,,,	Strain Imaging of a cathode in a Li-ion Battery		Co-author		HKICEAS-2048
11	Papers1	2011～2011,00,00,,,	Strain imaging of a Cu2S switching device	Academic Journal	Co-author	Elsevier, Current Applied Physics	doi:10.1016/j.cap.2011.04.004
12	Papers1	2011～2011,00,00,,,	Thermal strain imaging of chalcogenide in a phase change memory	Academic Journal	Co-author	Current Applied Physics 11 (2011) 731-734, Elsevier B.V.
13	Papers1	2010～2010,00,00,,,	Strain imaging of magnetic domain structures in the magnetic head of a hard disk drive	Academic Journal	Single-Author	Surface and Interface Analysis, JohnWiley & Sons, Ltd.	Surf. Interface Anal. 2010, 42, 1625–1628
14	Papers1	2010～2010,00,00,,,	Strain imaging of a perpendicular recording head in a Hard Disk Drive	Academic Journal	Single-Author	Journal of Magnetism and Magnetic Materials 322 (2010) 638–642, Elsevier B.V.
15	Papers1	2009/3～2009,03,00,,,	Strain imaging of a magnetic layer formed on an air bearing surface of a hard disk drive head for perpendicular recording	Academic Journal	Single-Author	Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures	Issue Date: Mar 2009 Volume: 27 Issue: 2, On page(s): 997 - 1000, Digital Object Identifier: 10.1116/1.3043457
16	Papers1	2009～2009,00,00,,,	Thermal Strain Imaging of Thermal Flying-Height-Controlled Magnetic Head	Academic Journal	Co-author	Applied Physics Express 2 (2009) 126504, The Japan Society of Applied Physics	Applied Physics Express 2 (2009) 126504
17	International academic conference8	2008/7～2008,07,00,,,	Strain imaging of a magnetic layer formed on an air bearing surface of a hard disk drive　head for perpendicular recording		Single-Author

PapersIn refereedAcademic JournalCo-author2020～2020

PapersIn-Situ imaging of Li intercalation in graphite particles in an Li-ion batteryAcademic JournalSingle-AuthorKEIJI TAKATAJournal of MicroscopyVol.00, Issue 0, pp1-42017/1/22～10.1111/jmi.12533

PapersIn refereedAcademic JournalCo-author2017～2017

PapersStrain imaging of a LiCoO2 cathode in a Li-ion batteryAcademic JournalCo-authorYuki Matsushita;Ryuma Osaka;Kenta Butsugan;Keiji TakataTHE JOURNAL OF CHEMICAL PHYSICS145, 1142012016～

International academic conferenceHigh-Resolution Observation of Electronic Properties of a Cathode Material in a Lithium-Ion BatteryCo-authorRyuma Osaka;Yuki Matsushita;Keiji TakataEH-TuE72016～pacsurf2016Hawaii

International academic conferenceHigh-Resolution Observation of Electronic Properties of an Anode Material in a Lithium-Ion BatteryCo-authorYuki Matsushita;Ryuma Osaka;Kenta Butsugan;Keisuke Nakayama;Yukiho Okuno;Keiji TakataEH-WeP-172016～pacsurf2016Hawaii

International academic conferenceMagnetic Strain Imaging of a Main Pole Tip and Upper Shield in a Hard Disk DriveCo-authorKenta Butsugan;Ryuma Osaka;Yuki Matsushita;Yukiho Okuno;Keisuke Nakayama;Keiji TakataNM-WeP-22016～pacsurf2016Hawaii

International academic conferenceImaging of dry-out in a LiCoO2 Cathode in a Li-ion BatteryCo-authorYukiho Okuno;Kenta Butsugan;Yuki Matsushita;Ryuma Osaka;Keisuke Nakayama;Keiji TakataEH-WeP-42016～pacsurf2016Hawaii

International academic conferenceStrain imaging of a LiCoO2 cathode in a Li-ion BatteryCo-authorKeisuke Nakayama;Yuki Matsushita;Ryuma Osaka;Kenta Butsugan;Yukiho Okuno;Keiji TakataEH-WeP-32016～pacsurf2016Hawaii

Academic presentationCo-author2016～

International academic conferenceMagnetic Strain Imaging of a Magnetic Tape Co-authorRyuma Osaka;Kento Mizo;Nozomi Yasuhara;Keiji TakataHKICEAS-20472015～HKICEAS2015Hong Kong

International academic conferenceIn-Situ High-Resolution Observation of Dryout of Electrolyte in a Lithium-Ion BatteryCo-authorKenta Butsugan;Masahiro Moto;Yuki Matsushita;Ryuma Osaka;Keiji TakataHKICEAS-20492015～HKICEAS2015Hong Kong

International academic conferenceStrain Imaging of a cathode in a Li-ion BatteryCo-authorYuki Matsushita;Masahiro Moto;Kenta Butsugan;Ryuma Osaka;Keiji TakataHKICEAS-20482015～HKICEAS2015Hong Kong

Academic presentationCo-author2015～

International academic conferenceIn refereedOtherSingle-Author2013/12/2～2013/12/6

PapersIn refereedAcademic JournalCo-author2012/5/5～2012/5/510.1143/APEX.5.047101

PapersStrain imaging of a Cu2S switching deviceIn refereedAcademic JournalCo-authorTAKATA, Keiji;Ryota Tamura;Toshihiro Kasama;Masataka Fukuyama;Shin Yokoyama;Hiroshi KajiyamaElsevier, Current Applied Physicsdoi:10.1016/j.cap.2011.04.0042011～Strain imaging of electrochemical behavior of a solid electrolyte Cu2S in switching devices for nonvolatile memories is presented. The precipitation and dissolution of Cu, and the nonstoichiometry changes cause changes in volume. Strain imaging we have proposed detects the volume changes through the surface displacements using scanning probe microscopy and provides high resolution images. We observed the distributions of the electrochemical reactions in Cu2S and located the Cu bridges causing switching.

PapersThermal strain imaging of chalcogenide in a phase change memoryIn refereedAcademic JournalCo-authorTAKATA, Keiji;Hiroya Maekawa;Hiroki EndoCurrent Applied Physics 11 (2011) 731-734, Elsevier B.V.2011～Thermal strain imaging using a scanning probe microscope enables us to observe thermal distribution with high resolution. A phase change memory (PCM) based on chalcogenide glasses switches their two stable states having low and relatively high resistances by Joule heating. Images obtained by thermal strain imaging revealed that Joule heating was mainly generated in particular regions and some boundaries. The large fluctuation of increases in temperature in the active area should greatly affect phase change in PCM.

PapersStrain imaging of magnetic domain structures in the magnetic head of a hard disk driveIn refereedAcademic JournalSingle-AuthorTAKATA, KeijiSurface and Interface Analysis, JohnWiley & Sons, Ltd.Surf. Interface Anal. 2010, 42, 1625–16282010～Detection and imaging of magnetic-field-induced strains using scanning probe microscopy enable us to observe magnetic domain structures. Domain structures in a magnetization reversal process of the lateral-recording head in a hard disk drive were investigated by scanning over the air-bearing surface of the head. External magnetic fields were applied by the writing coil. In the process, magnetic domains in the bottom pole were divided into right and left regions in the cross-track direction, having opposite magnetizations. The domain boundary moved to right or left according to writing currents, and vanished by larger currents than 15mA. Hemispherical domain structures with a diameter of around 0.6 μm, consisting of two opposite magnetizations in the direction of the appliedmagnetic field, were observed in several portions of the bottom pole. The domain structures also vanished with increasing field strength.

PapersStrain imaging of a perpendicular recording head in a Hard Disk DriveIn refereedAcademic JournalSingle-AuthorTAKATA, KeijiJournal of Magnetism and Magnetic Materials 322 (2010) 638–642, Elsevier B.V.2010～Imaging of magnetic-field-induced strains using scanning probe microscopy enables us to observe magnetic domain structures and magnetic force distributions. This method has an ability of observing magnetic structures in deep portions along with surface structures. We observed an air-bearing surface of a perpendicular recording head in a hard disk drive in large areas including the whole yokes, and investigated characteristics of the magnetic poles and layers subjected to magnetic fields produced by writing coil currents. Attractive forces independent of the field directions acted between the upper and lower yokes made by soft material, which generated surface displacements in the ABS. The signals were second-harmonic oscillations for alternating currents without a dc bias, and the amplitude images represented the field distribution. Meanwhile, fixed magnetic charges in both ends of the read sensor, which were produced by the hard-bias film, were subjected to the fields. The fixed charges, which hardly changed by the fields, lead to strains depending on the field directions, and generated specific contrasts of one pair of bright-dark spots in the strain images. In the absence of surface underlayer, the fields by the writing coil broke into the read sensor sandwiched by the shield layers.

Academic presentationCo-author2009/3～

PapersStrain imaging of a magnetic layer formed on an air bearing surface of a hard disk drive head for perpendicular recordingIn refereedAcademic JournalSingle-AuthorTAKATA, KeijiJournal of Vacuum Science & Technology B: Microelectronics and Nanometer StructuresIssue Date: Mar 2009 Volume: 27 Issue: 2, On page(s): 997 - 1000, Digital Object Identifier: 10.1116/1.3043457 2009/3～The detection and imaging of magnetic-field-induced strains using scanning probe microscopy enable us to observe magnetic domain structures. A perpendicular recording head in a hard disk drive has been observed in this method in order to investigate distribution of magnetic fields applied to a recording disk. In perpendicular recording, the magnetic field circuit consists of a main pole, a main pole tip, a soft magnetic underlayer (SUL) in the disk and a return pole. The authors formed a magnetic layer on the air bearing surface of the head, and observed the layer subjected to magnetic fields by the write head. The layer plays a role in the SUL and constitutes a part of the magnetic field circuit. The authors imaged the magnetic-field-induced strains in the layer and discussed field distribution in recording media.

PapersThermal Strain Imaging of Thermal Flying-Height-Controlled Magnetic HeadIn refereedAcademic JournalCo-authorTAKATA, Keiji;Noriyasu Ichimei;Mitsuhiro OkudaApplied Physics Express 2 (2009) 126504, The Japan Society of Applied PhysicsApplied Physics Express 2 (2009) 1265042009～Excellent resolutions of scanning probe microscopes (SPMs) enable us to image thermal strains with high special resolutions and with high sensitivities. Recently, thermal expansion has been applied for controlling a gap between a magnetic head and a disk in a hard disk drive, which was a key technology for high areal density recording. An SPM can detect the thermal strains generated in the head and image the distribution along with topography. The thermal strain images obtained at several frequencies, which showed the extent and the magnitude of the thermal protrusions quantitatively, revealed frequency dependence of dynamic flying-height control.

Academic presentationCo-author2008/9～

International academic conferenceStrain imaging of a magnetic layer formed on an air bearing surface of a hard disk drive　head for perpendicular recordingSingle-AuthorTAKATA,Keiji2008/7～International conference of nanoscience and technologyUSA

TAKATA, Keiji

Faculty, Department/Institute

Academic status (qualification)

Undergraduate Degrees・University

Graduate Degrees・University

Academic Degrees

Research fields

Research topics

Awards

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Research Publications

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Courses Taught