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NISHIKAWA Hiroaki

    Department of Biomedical Engineering　Professor/Manager
Last Updated :2024/04/19

Researcher Information

Degree

  • Ph. D.（1998/03 Osaka University）

URL

Research funding number

  • 50309267

ORCID ID

J-Global ID

Research Interests

  • Oxide electronics   Biomaterials   Materials engineering   Solid state chemistry   

Research Areas

  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Electronic devices and equipment
  • Nanotechnology/Materials / Composite materials and interfaces
  • Nanotechnology/Materials / Thin-film surfaces and interfaces
  • Nanotechnology/Materials / Crystal engineering
  • Nanotechnology/Materials / Applied materials

Academic & Professional Experience

  • 2018/04 - Today  Kindai UniversityFaculty of Biology-Oriented Science and Technology, Department of Biomedical Engineering教授
  • 2010/04 - 2018/03  Kindai UniversityFaculty of Biology-Oriented Science and Technology, Department of Biomedical Engineering准教授
  • 2011/12 - 2012/03  Osaka UniversityThe Institute of Scientific and Industrial Research客員准教授（兼任）
  • 2008/04 - 2010/03  Kindai UniversityFaculty of Biology-Oriented Science and Technology, Department of Electronic Systems and Information Engineering准教授
  • 2007/09 - 2008/09  オランダ王国国立Twente大学理工学部無機材料科学グループ客員研究員（兼任）
  • 2003/04 - 2008/03  Kindai UniversityFaculty of Biology-Oriented Science and Technology, Department of Electronic Systems and Information Engineering講師
  • 1998/04 - 2003/03  Kindai UniversityFaculty of Biology-Oriented Science and Technology, Department of Electronic Systems and Information Engineering助手
  • 1997/04 - 1998/03  日本学術振興会特別研究員DC2

Education

  • 1995/04 - 1998/03  大阪大学大学院  理学研究科  無機及び物理化学専攻博士後期課程
  • 1993/04 - 1995/03  大阪大学大学院  理学研究科  無機及び物理化学専攻博士前期課程
  • 1989/04 - 1993/03  Kindai University  Faculty of Science and Engineering  電子工学科

Association Memberships

  • The Institute of Electrical Engineers of Japan   The Ceramic Society of Japan   THE MATERIALS SCIENCE SOCIETY OF JAPAN   The Japan Society of Vacuum and Surface Science   THE MATERIALS RESEARCH SOCIETY OF JAPAN   THE JAPANESE SOCIETY FOR BIOMATERIALS   THE JAPAN SOCIETY OF APPLIED PHYSICS   THE PHYSICAL SOCIETY OF JAPAN   

Published Papers

  • Tomofumi Mizuyama; Hiroaki Nishikawa
    IEEJ Transactions on Electronics, Information and Systems Institute of Electrical Engineers of Japan (IEE Japan) 142 (10) 1060 - 1063 0385-4221 2022/10 [Refereed]
  • Hiroaki Nishikawa; Shinji Umatani; Tomofumi Mizuyama; Akihiro Hiraoka; Katsuhiro Mikami
    Sensors MDPI AG 21 (21) 7326-1 - 7326-8 2021/11 [Refereed]
     
    The transfer of ferroelectric and piezoelectric BaTiO3 epitaxial thin films from an original MgO(100) single-crystal substrate to a polyethylene terephthalate (PET) sheet has been studied to fabricate flexible epitaxial functional oxides. The outline of our previous transfer process is as follows: the epitaxial BaTiO3 thin films were deposited on the MgO(100). Then, the surface of the BaTiO3 was adhered onto a PET sheet. Finally, only the MgO(100) substrate was dissolved in a phosphoric aqueous solution, which resulted in the transfer of the epitaxial BaTiO3 thin film from the MgO(100) to a PET sheet. To establish this transfer process, our aim was to prevent any damage, such as cracks and exfoliation, during the transfer of the epitaxial functional oxides. We found that a Pt buffer layer with a ductile nature was effective for improving the quality of transferred epitaxial BaTiO3 thin films. Moreover, the epitaxial BaTiO3 thin films showed a drastic shrinkage of ca. 10%. The surfaces of the shrunk, epitaxial BaTiO3 thin films showed giant wrinkles with a micrometer-order amplitude and a 10-μm-order periodicity without any damage. The epitaxial BaTiO3 thin films with giant wrinkles, accompanied by drastic shrinkage, are similar to the thin films that are coated on a pre-stretched elastomer, which is one of the fabrication processes of stretchable devices.
  • Tomofumi Mizuyama; Norimitsu Hirosaki; Hiroaki Nishikawa
    IEEJ Transactions on Electronics, Information and Systems Institute of Electrical Engineers of Japan (IEE Japan) 141 (7) 782 - 783 0385-4221 2021/07 [Refereed]
  • Akihiro Hiraoka; Kohei Fujiwara; Hiroaki Nishikawa
    IEEJ Transactions on Electronics, Information and Systems Institute of Electrical Engineers of Japan (IEE Japan) 141 (7) 767 - 770 0385-4221 2021/07 [Refereed]
  • Katsuhiro Mikami; Yue Zhao; Masato Morita; Tetsuo Sakamoto; Hiroaki Nishikawa
    Journal of Nondestructive Evaluation Springer Science and Business Media LLC 40 (1) 12-1 - 12-9 0195-9298 2021/03 [Refereed]
  • Hiroaki Nishikawa; Fumiya Itani; Tadao Kawaguchi; Hidekazu Tanaka; Nobuyuki Iwata
    Solid State Communications Elsevier BV 323 114105-1 - 114105-5 0038-1098 2021/01 [Refereed]
  • Ayaka Saito; Hiroaki Nishikawa
    Transactions of the Materials Research Society of Japan The Materials Research Society of Japan 45 (5) 183 - 186 1382-3469 2020/10 [Refereed]
  • S. Umatani; H. Nishikawa
    IEEJ Transactions on Electronics, Information and Systems 139 (3) 211 - 212 2019/03 [Refereed]
  • Hiroaki Nishikawa; Tsukasa Hasegawa; Akiko Miyake; Yuichiro Tashiro; Satoshi Komasa; Yoshiya Hashimoto
    APPLIED SURFACE SCIENCE ELSEVIER SCIENCE BV 427 (Part B) 458 - 463 0169-4332 2018/01 [Refereed]
     
    The dependence of the surface morphology and chemical composition of hydroxyapatite (HA) thin films on the laser fluence and ambient gas pressure during their formation by pulsed laser deposition was studied as the first step to investigate the effect of physical and chemical interactions between the ablated chemical species and ambient gas molecules on HA film formation. It was found that a higher fluence could decrease the number of large protrusions on the surface of HA thin films. However, too high a fluence caused a phosphorus deficiency from the stoichiometric value, particularly in the case of lower ambient gas pressure. It was also found that for lower fluences, the atomic species among the ablated chemical species were easily scattered by collision processes with ambient gas molecules. This was caused by the lower velocity of the ablated chemical species and higher ambient gas pressure, which induced a shorter mean free path. In addition, these collision processes played an important role in the adsorption, migration, and re-evaporation of the ablated chemical species on the substrate via chemical reactions. (C) 2017 Elsevier B.V. All rights reserved.
  • Hiroaki Nishikawa; Shinji Umatani
    MATERIALS LETTERS ELSEVIER SCIENCE BV 209 330 - 333 0167-577X 2017/12 [Refereed]
     
    The effect of the pulse repetition rate of the ablation laser on surface protrusion density was investigated for hydroxyapatite thin films deposited using pulsed laser deposition. Atomic force microscope surface images showed a marked decrease in surface protrusion density at lower pulse repetition rate, while protrusion-free areas exhibited similar morphologies independent of the pulse repetition rate. These results indicate that the surface protrusions were not formed or enlarged from surface migration of atomic species on the surface, which formed the smooth surface of the protrusion-free area. The postulated origin of the protrusions was large particles or droplets produced directly from the target irradiated with the ablation laser. These results suggest that the optimum pulse repetition rate for protrusion-free hydroxyapatite thin film surfaces is <= 3 Hz. (C) 2017 Elsevier B.V. All rights reserved.
  • Hiroaki Nishikawa; Tsukasa Hasegawa; Akiko Miyake; Yuichiro Tashiro; Yoshiya Hashimoto; Daveh H. A. Blank; Guus Rijnders
    MATERIALS LETTERS ELSEVIER SCIENCE BV 165 95 - 98 0167-577X 2016/02 [Refereed]
     
    Variation of the Ca/P ratio in hydroxyapatite (Ca-10(PO4)(6)(OH)(2)) thin films was studied in relation to the spot size of the ablation laser for two different spatial energy distributions in pulsed laser deposition. One energy distribution is the defocus method with a raw distribution and the other is the projection method without the weak portion at the edges of the ablation laser spot. A Ca/P ratio closer to that of stoichiometry was obtained with the larger spot sizes for both methods, and with the projection method compared to the defocus method. It is considered that a more uniform spatial energy distribution of the ablation laser improves the Ca/P ratio. (C) 2015 Elsevier B.V. All rights reserved.
  • Hiroaki Nishikawa; Ryota Yoshikawa
    Transactions of the Materials Research Society of Japan The Materials Research Society of Japan 40 (2) 111 - 114 1382-3469 2015/06 [Refereed]
     
    To prepare hydroxyapatite (Ca10(PO4)6(OH)2) thin films with a stoichiometric Ca/P ratio via pulsed laser deposition (PLD), the spot area of the laser pulse was changed independently of the laser fluence. To maintain a constant fluence when the spot area was changed, the total energy irradiated on the target surface was adjusted relative to the spot area. We found that the spot area dramatically changed the Ca/P ratio of the hydroxyapatite thin films that were prepared via PLD with a constant fluence. The best Ca/P ratio of 1.72 ± 0.13, which is close to the stoichiometric ratio (1.67), is achieved with a spot area and a fluence of 3.8 mm2 and 2.4 J/cm2, respectively. We report on the importance of the spot area in the PLD technique for the first time.
  • Yoshiya Hashimoto; Hiroaki Nishikawa; Masanobu Kusunoki; PeiQi Li; Shigeki Hontsu
    DENTAL MATERIALS JOURNAL JAPANESE SOC DENTAL MATERIALS DEVICES 34 (3) 345 - 350 0287-4547 2015/06 [Refereed]
     
    Cell sheet technology is a scaffold-free method for tissue reconstruction. A sheet-shaped scaffold would be suitable for the regeneration of periodontal membrane. We designed a stem cell sheet combining human mesenchymal stromal cells (hMSCs) and a 10-mu m thick biological apatite (BAp) membrane fabricated with an ArF pulsed laser ablation for periodontal regeneration. X-ray diffraction showed that crystalline hydroxyapatite (HAp) was present in BAp and HAp membranes after post-annealing. Energy dispersive analysis of the BAp membrane revealed peaks of Na and Mg in addition to Ca and P. Approximately 3x10(4) hMSCs were cultured on BAp and HAP membranes for 7 and 14 days. From in vitro assays, hMSCs grew faster and had higher osteoblast differentiation when cultured on the BAp membrane than did the cell culture on the HAp membrane. Stem cell sheets combined with a BAp membrane may have potential applications in guided bone regeneration and osteoconductive scaffolds.
  • J. E. Kleibeuker; Z. Zhong; H. Nishikawa; J. Gabel; A. Mueller; F. Pfaff; M. Sing; K. Held; R. Claessen; G. Koster; G. Rijnders
    PHYSICAL REVIEW LETTERS AMER PHYSICAL SOC 113 (23) 237402-1 - 237402-5 0031-9007 2014/12 [Refereed]
     
    We report the formation of a nonmagnetic band insulator at the isopolar interface between the antiferromagnetic Mott-Hubbard insulator LaTiO3 and the antiferromagnetic charge transfer insulator LaFeO3. By density-functional theory calculations, we find that the formation of this interface state is driven by the combination of O band alignment and crystal field splitting energy of the t(2g) and e(g) bands. As a result of these two driving forces, the Fe 3d bands rearrange and electrons are transferred from Ti to Fe. This picture is supported by x-ray photoelectron spectroscopy, which confirms the rearrangement of the Fe 3d bands and reveals an unprecedented charge transfer up to 1.2 +/- 0.2 e(-)/interface unit cell in our LaTiO3/LaFeO3 heterostructures.
  • Kazuya Hanada; Miyoshi Yokura; Masatsugu Nagashima; Yuichi Nakamura; Hiroaki Nishikawa; Yuri Strzhemechny; Zorica Orel; Sanapa Lakshmi Reddy; Yukiko Izumi; Shigehisa Tomita; Tamio Endo
    JAPANESE JOURNAL OF APPLIED PHYSICS IOP PUBLISHING LTD 53 (5) 05FB23-1 - 05FB23-6 0021-4922 2014/05 [Refereed]
     
    A plasma-irradiated poly(ethylene terephthalate) (PET) film has a long lifetime of bonding capability. To clarify its origin, a PET film was irradiated with oxygen plasma. It was then exposed to normal atmosphere including water vapor. FTIR absorption on the irradiated and non-irradiated films was measured at different times after the start of evacuation. The irradiated film has a larger amount of OH than the non irradiated film, and OH is generated on the film surface. The irradiated film has a larger amount of adsorbed water, because the surface is activated by the created OH. The adsorbed water is desorbed rapidly with increasing evacuation time in the non irradiated film, but it is desorbed more gradually in the irradiated film. Water has hydrogen bonds with OH; thus, the water desorption is suppressed. The OH absorption band is shifted to the lower wave number side owing to the hydrogen bonds. The irradiated surface may be protected by the water from the atmosphere. (C) 2014 The Japan Society of Applied Physics
  • Miyoshi Yokura; Kenichi Uehara; Kazuya Hanada; Yoshinobu Nakamura; Hiroaki Nishikawa; Tetsuo Tsuchiya; Sanapa Lakshmi Reddy; Reji Philip; Yukiko Izumi; Shigehisa Tomita; Tamio Endo
    JAPANESE JOURNAL OF APPLIED PHYSICS IOP PUBLISHING LTD 53 (5) 05FB21-1 - 05FB21-6 0021-4922 2014/05 [Refereed]
     
    To clarify the bonding mechanism for the plasma-irradiated PET films and the origin of the long lifetime of the bonding ability, we soaked the irradiated films in various types of liquid reagent, then tried to bond them by heat-pressing. The irradiated films do not lose the bonding ability after soaking in water, acid, alkali, and organic solvents, whereas they lose it after soaking in ionic solutions of AlCl3 and FeCl3. The COOH is created on the surface by the irradiation, but it is consumed by the chemical reaction with Al and Fe ions. This is the origin of the inactivation of the irradiated surface and the disappearance of the bonding ability after the soaking. The result supports our proposal of "dehydrated condensation reaction" concerning COOH as the bonding mechanism. The irradiated films should be stable in a normal atmosphere for a long time because they are not subjected to water, acid, alkali, and organic solvents. c 2014 The Japan Society of Applied Physics
  • Hiroaki Nishikawa; Yusuke Morita; Masanobu Kusunoki; Shigeki Hontsu; Hidekazu Tanaka; Tamio Endo
    JAPANESE JOURNAL OF APPLIED PHYSICS IOP PUBLISHING LTD 53 (5) 05FB06-1 - 05FB06-4 0021-4922 2014/05 [Refereed]
     
    In this study, we prepared a uniaxially oriented oxide on a flexible polymer substrate. We first grew [100] oriented SrTiO3 (STO) on a MgO(100) substrate. After bonding the STO film to a poly(ethylene naphthalete) (PEN) sheet with a photoresist, we etched the MgO substrate with a phosphoric acid solution to transfer the oxide film to the PEN sheet. The thin (300nm) STO films did not crack after release, even after bending the sheet around a rod with a 1cm radius, while the thicker (800 nm) films did. Ultimately, this process could be adapted to prepare a flexible epitaxial oxide. (C) 2014 The Japan Society of Applied Physics
  • Yasuhiro Sakoishi; Ryo Iguchi; Hiroaki Nishikawa; Shigeki Hontsu; Takashi Hayami; Masanobu Kusunoki
    APPLIED PHYSICS EXPRESS IOP PUBLISHING LTD 6 (11) 115501-1 - 115501-3 1882-0778 2013/11 [Refereed]
     
    A method of fabricating c-axis-oriented hydroxyapatite film on a quartz crystal microbalance (QCM) sensor was investigated. ZnO was used as a template to obtain a hexagonal hydroxyapatite crystal of uniaxial orientation. The ZnO was grown as a c-axis film on a Au/quartz with the surface structure of a QCM sensor. Under optimized conditions, hydroxyapatite was deposited by pulsed laser deposition. X-ray diffraction showed the hydroxyapatite film to be oriented along the c-axis. Because Au and ZnO are applied to many devices, the anisotropic properties of hydroxyapatite may be incorporated into these devices as well as QCM sensors. (C) 2013 The Japan Society of Applied Physics
  • T. Nishigaki; H. Nishikawa; M. Kusunoki; S. Hontsu
    Bioceramics Development and Applications S1-008 2013/05 [Refereed]
  • Miyoshi Yokura; Kazuya Hanada; Kenichi Uehara; Yuichi Nakamura; Lakshmi Sanapa Reddy; Hiroaki Nishikawa; Masatsugu Nagashima; Tamio Endo
    JAPANESE JOURNAL OF APPLIED PHYSICS JAPAN SOC APPLIED PHYSICS 51 (11) 11PG14-1 - 11PG14-6 0021-4922 2012/11 [Refereed]
     
    Poly(ethylene terephthalate) (PET) films can be bonded directly by oxygen plasma irradiation and heat press at low temperatures of 100-160 degrees C. The irradiated films were kept in the atmosphere for six years, yet they can be bonded tightly. The irradiated surface is extremely active just after the irradiation, and it is considerably active after five years. Dry- and wet-peel tests suggest hydrogen bonding and chemical bonding. The films are bonded by these two elements at lower press temperatures, while by the pure chemical bonding at higher temperatures. Fourier transform infrared spectroscopy (FTIR) results on the non-irradiated, irradiated and bonded samples indicate that OH and COOH groups are created at the surface, they are responsible for the both bondings. Dehydrated condensation reaction is proposed for the chemical bonding. The hydrogen bonding is broken by water penetration, causing smaller peel strength under the wet-peel test. Cross-linking layer may be the origin for the long lifetime. (C) 2012 The Japan Society of Applied Physics
  • Daisuke Ito; Katsumi Kotani; Tomoki Miyake; Hiroaki Nishikawa; Shigeki Hontsu; Masanobu Kusunoki
    IEEJ Transactions on Electronics, Information and Systems Institute of Electrical Engineers of Japan (IEE Japan) 132 (11) 1722 - 1726 0385-4221 2012/11 [Refereed]
     
    We studied a method to obtain superconductivity even in very thin films of YBa2Cu3Oy (YBCO). These thinner YBCO films will be able to be applied to optics/superconductivity (opt/super) converters with high optical sensitivity. Opt/super converters composed of YBCO nano-bridges or nano-wires require a low critical current that is determined by the film thickness. According to X-ray diffraction, critical temperature (Tc) and residual resistivity ratio for the substrates of MgO (100), SrTiO3 (100) and NdGaO3 (110), superconducting features are influenced by the lattice mismatching layer in YBCO closing to a hetero-epitaxy interface between YBCO and single crystal substrate. YBCO films with different thicknesses varying from 80 to 10nm were prepared on SrTiO3, using a suitable temperature. The values of Tc slightly decreased when reducing YBCO thickness from 80 to 20 nm, and then declined sharply at less than 20nm. It is considered that a layer in the beginning of deposition less than 20nm causes stress in the crystal lattice. The Tc of 20 nm YBCO film on SrTiO3 was 80.8 K. It can work above liquid N2 temperature.
  • Shigeki Hontsu; Yoshiya Hashimoto Dr.; Yoshihiro Yoshikawa; Masanobu Kusunoki; Hiroaki Nishikawa; Akihiro Ametani
    Journal of Hard Tissue Biology 21 (2) 181 - 188 1341-7649 2012 [Refereed]
     
    To develop an improved surface conformation of titanium web (TW) scaffold, we examined the in vitro and in vivo biocompatibility of a thin hydroxyapatite (HA) deposited by pulsed laser ablation. Thin HA film was deposited on titanium discs using an pulsed laser operating at a repletion rate of 10 Hz and annealed by heating at 380°C for 1 h. The presence of HA not only along the surface but also in the TW inner region was confirmed by the elementary mapping of calcium, phosphorous, and titanium. X-ray diffraction pattern showed that crystalline HA was present in the HA coating. Microscopic images after actin staining with rhodamine phalloidin revealed that the spread of clonal stromal cells was markedly greater on HA coating than on untreated TW. When infused with clonal stromal cells, the HA-coated TW could indeed generate bone formation in the backs of nude mice. However, the appearance of new bone was not enhanced by the HA coating, likely because air in the porous scaffold during cell loading reduces the cell-scaffold contact. Mild vacuum loading techniques might enable differences of osteo-differentiation between HA-coated TW and non-coated TW to emerge. © 2012 The Hard Tissue Biology Network Association Printed in Japan, All rights reserved.
  • Takashi Hayami; Shigeki Hontsu; Yuichi Higuchi; Hiroaki Nishikawa; Masanobu Kusunoki
    CLINICAL ORAL IMPLANTS RESEARCH WILEY-BLACKWELL 22 (7) 774 - 776 0905-7161 2011/07 [Refereed]
     
    Objective: To impart rapid and durable osteoconductivity to implants, a commercial titanium screw implant was coated with stoichiometric hydroxyapatite (HA; 50 nm thick), and then with bovine hydroxyapatite (B-HA; 300 nm thick) using the pulsed laser deposition technique. As control specimens, a commercial implant coated with HA (20 mu m thick) using the flame spraying method (sprayed implant) and a simple titanium implant (basic implant) was used. Methods: The osteoconductivities of these three types of implant, after implantation for 4-24 weeks, were histologically evaluated. Results: Peeling of HA from the sprayed implant was observed by scanning electron microscopic observation. In the fourth postoperative week, the bilayered implant was already closely adhered to bone. On the other hand, the basic implant was surrounded by a gap containing connective tissue. With the sprayed implant, the bone adhered to the thick HA coating. Conclusion: The bilayer deposition technique supplies quick and long-term fixation of implants to bone, because the B-HA film dissolves to aid osteoconduction right immediately after implantation and the HA thin film maintains osteoconduction without dissolution. Neither of the thin-film fractures easily compared with thick coatings.
  • Masanobu Kusunoki; Yoshiaki Kawakami; Taiyo Matsuda; Hiroaki Nishikawa; Takashi Hayami; Shigeki Hontsu
    APPLIED PHYSICS EXPRESS IOP PUBLISHING LTD 3 (10) 100073-1 - 100073-3 1882-0778 2010 [Refereed]
     
    A large hydroxyapatite (HA) sheet of 50 mm diameter was constructed using a new fabrication process. The HA sheet was prepared by pulsed laser deposition (PLD) and then separated from the substrate. An intermediate layer of spin-coated photoresist between the PLD film and the substrate was dissolved in acetone to enable the separation. Sufficient crystallinity was obtained after postannealing. The area of the HA sheet prepared by the proposed process was approximately 20 times larger than that of the HA sheet prepared by the previous process. The proposed process can also be used for larger sheets. The HA sheet has promise in medical and dental applications. (C) 2010 The Japan Society of Applied Physics
  • 楠正暢; 東郷秀孝; 和田拓士; 橋本典也; 西川博昭; 本津茂樹
    電気学会論文誌C分冊 129 (11) 2014 - 2018 2009/11 [Refereed]
  • H. Boschker; M. Mathews; E. P. Houwman; H. Nishikawa; A. Vailionis; G. Koster; G. Rijnders; D. H. A. Blank
    PHYSICAL REVIEW B AMER PHYSICAL SOC 79 (21) 214425  1098-0121 2009/06 [Refereed]
     
    Epitaxial La0.67Sr0.33MnO3 (LSMO) ferromagnetic thin films were coherently grown on NdGaO3 (NGO) substrates with different crystal orientations of the surface plane. On the (110)(o)- and (001)(o)-oriented substrates, the film grows in the (001)(pc) orientation, and on the (100)(o)-, (010)(o)-, and (112)(o)-oriented substrates the film is (011)(pc) oriented (we will use subindices o and pc for the orthorhombic and pseudocubic crystal structures, respectively). The lattice parameters and pseudocube angles of the deformed LSMO pseudocube have been determined from x-ray diffraction measurements. The in-plane magnetic easy and hard directions of these films have been determined from the dependence of the remnant magnetization on the angle of the in-plane applied field. For all substrate orientations there is a strong in-plane uniaxial magnetic anisotropy, determined by the crystal directions of the substrate surface. The easy and hard magnetic-anisotropy directions are explained consistently by the (bulk) inverse magnetostriction model, except for the film on NGO (112)(o).
  • Hiroaki Nishikawa; Evert Houwman; Hans Boschker; Mercy Mathews; Dave H. A. Blank; Guus Rijnders
    APPLIED PHYSICS LETTERS AMER INST PHYSICS 94 (4) 042502  0003-6951 2009/01 [Refereed]
     
    The in-plane magnetic anisotropy is studied for pseudocubic {011}(pc) oriented La0.67Sr0.33MnO3 (LSMO) thin film grown on orthorhombic NdGaO3(NGO)(112)(o) (the subindices "pc" and "o" indicate the pseudocubic and orthorhombic lattice structure, respectively). The direction of the in-plane remanent magnetization of LSMO thin films with different thicknesses is determined. With increasing film thickness the easy axes rotate and the anisotropy changes from uniaxial to biaxial. This is associated with the increasing symmetry of the LSMO with increasing thickness, starting with a monoclinic LSMO structure at the nonrectangular NGO(112)(o) surface unit cell of the substrate, developing into an orthorhombic structure at the top part of the thickest films.
  • HAYAMI Takashi; NISHIKAWA Hiroaki; HIGUCHI Yuichi; HASHIMOTO Noriya; KUSUNOKI Masanobu; HONTSU Shigeki; SHIBUE Tadashi; YAMAMOTO Masao
    Journal of JSEM 日本実験力学会 8 (2) 127 - 132 1346-4930 2008/12 [Refereed]
  • Hiroaki Nishikawa; Ryota Hatanaka; Masanobu Kusunoki; Takashi Hayami; Shigeki Hontsu
    APPLIED PHYSICS EXPRESS JAPAN SOC APPLIED PHYSICS 1 (8) 088001-1 - 088001-3 1882-0778 2008/08 [Refereed]
     
    Hydroxyapatite (HAp) is one of the most widely used materials for tissue culture scaffolding in regenerative medicine. To apply HAp as a suitable material for tissue culture scaffolding, we have developed freestanding HAp membranes that can be directly transplanted "as is" into a diseased site after tissue culturing. These freestanding HAp membranes are highly biocompatible, provide early cell proliferation and differentiation, and their flexibility allows some degree of configuration to the target site. This tissue culture scaffold is ideal from the standpoint of harvesting tissue and directly transplanting it to the diseased site. (C) 2008 The Japan Society of Applied Physics.
  • Y. Hashimoto; M. Kawashima; R. Hatanaka; M. Kusunoki; H. Nishikawa; S. Hontsu; M. Nakamura
    JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE SPRINGER 19 (1) 327 - 333 0957-4530 2008/01 [Refereed]
     
    In the current studies, we deposited ultra-thin hydroxyapatite films on a pure titanium substrate by pulsed laser deposition, and we examined the effects of these surfaces on rat bone marrow (RBM) cells. This method allowed deposition of 500-, 2,000-, and 5,000-angstrom-thick hydroxyapatite films. X-ray diffraction showed that the amorphous films recrystallized to a hydroxyapatite crystal structure after annealing. The proliferation of RBM cells was unaffected by the hydroxyapatite films, but osteocalsin and alkaline phosphatase mRNA and protein levels were elevated in cells grown on 2,000- and 5,000-angstrom-thick films. These results indicate that ultra-thin hydroxyapatite films generated by pulsed laser deposition are better at promoting osteogenesis than pure titanium surfaces.
  • Y. Hashimoto; M. Kawashima; R. Hatanaka; M. Kusunoki; H. Nishikawa; S. Hontsu; M. Nakamura
    JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE SPRINGER 18 (7) 1457 - 1464 0957-4530 2007/07 [Refereed]
     
    In the current studies, we deposited ultra-thin hydroxyapatite films on a pure titanium substrate by pulsed laser deposition, and we examined the effects of these surfaces on rat bone marrow (RBM) cells. This method allowed deposition of 500-, 2000-, and 5000-angstrom-thick hydroxyapatite films. X-ray diffraction showed that the amorphous films recrystallized to a hydroxyapatite crystal structure after annealing. The proliferation of RBM cells was unaffected by the hydroxyapatite films, but osteocalsin and alkaline phosphatase mRNA and protein levels were elevated in cells grown on 2000- and 5000-angstrom-thick films. These results indicate that ultra-thin hydroxyapatite films generated by pulsed laser deposition are better at promoting osteogenesis than pure titanium surfaces.
  • Takashi Hayami; Kazuaki Matsumura; Masanobu Kusunoki; Hiroaki Nishikawa; Shigeki Hontsu
    MATERIALS LETTERS ELSEVIER SCIENCE BV 61 (13) 2667 - 2670 0167-577X 2007/05 [Refereed]
     
    To impart good cell adhesion to poly(vinyl alcohol) hydrogel (PVA-H) as an artificial articular cartilage, hydroxyapatite thin film 300 nm thick was deposited by a pulsed laser deposition technique on PVA-H, which has virtually no cell adhesion. A cell culture method was used to study the effect of hydroxyapatite deposition on PVA-H upon cell adhesion among mouse fibroblasts. The cell adhesion of water content 33% PVA-H coated with the amorphous hydroxyapatite film showed a maximum as high as that of commonly used tissue culture dishes. This technique was also effective for improving cell adhesion, even on a higher water content (53%) PVA-H. This is a novel technique to improve the biocompatibility and attachment of PVA-H and with the underlying bone and natural cartilage. (C) 2006 Elsevier B.V. All rights reserved.
  • Haruka Imai; Masanobu Kusunoki; Yoshiya Hashimoto; Hiroaki Nishikawa; Shigeki Hontsu
    IEEJ Transactions on Electronics, Information and Systems Institute of Electrical Engineers of Japan 127 (11) 1839 - 1842 1348-8155 2007 [Refereed]
     
    Biological molecular adsorption on crystal hydroxyapatite (HAp) and amorphous Ca10(PO4)6(OH)2 was investigated using quartz crystal microbalance (QCM) method. The pulsed laser ablation (PLA) was applied to coat both kind films for QCM sensors. A crystal HAp sensor was prepared with thermal treatment during the fabrication process. An amorphous Ca10(PO4)6(OH)2 sensor was prepared without any thermal treatment. Not only crystal HAp but amorphous Ca10(PO4)6(OH)2 showed good adsorptive feature compared with conventional QCM on the market. The result showed that a low temperature deposition of HAp is adaptable to polymer-based materials for medical purposes.
  • 生体アパタイト超薄膜被覆インプラントの生体親和性
    本津茂樹; 川島将実; 西川博昭; 楠正暢; 速水尚; 大橋芳夫; 樋口裕一; 橋本典也
    バイオマテリアル-生体材料- 24 353 - 260 2006/09 [Refereed]
  • S Hontsu; K Agemura; H Nishikawa; M Kusunoki
    IEICE TRANSACTIONS ON ELECTRONICS IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG E89C (2) 151 - 155 0916-8524 2006/02 [Refereed]
     
    A coplanar type lumped-element 6-pole microwave Chebyshev bandpass filter (BPF) of center frequency (f(0)) 2.0 GHz and fractional bandwidth (FBW) 1.0% was designed. For the design method, theory of direct coupled resonator filters using K-inverters was employed. Coplanar type lumped-element BPFs are composed of a meander-line L and interdigital C elements. The frequency response was simulated and analyzed using an electromagnetic field simulator (Sonnet-EM). Further, the changes in fo and FBW of the BPF were also realized by the mechanical tuning method.
  • S Hontsu; K Iguchi; K Agemura; H Nishikawa; M Kusunoki
    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC 15 (2) 972 - 975 1051-8223 2005/06 [Refereed]
     
    The tunable filter has variable center frequency (f(o)) and variable bandwidth (BW) that can be adapted to software defined radio. In our mechanical tunable filter, capacitance of each element is changed by motion of dielectric plate that is located above the capacitive elements. The dielectric plates are moved by piezoelectric bimorph actuators. Tuning test of the fo in a cryocooler is performed using an actual superconducting filter fabricated with YBa2Cu3Oy thin film deposited on an MgO (100) substrate. Taking into account of the effective change of parallel capacitance to ground plane by movement of dielectric plates above the element, we choose the coplanar wave guide type filter that has the ground plane on top side of the substrate. Suitable design of the mechanically tunable superconducting lumped element filter is discussed.
  • M Kusunoki; M Kawasima; H Nishikawa; K Morimoto; T Hayami; S Hontsu; T Kawai
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS INST PURE APPLIED PHYSICS 44 (8-11) L326 - L327 0021-4922 2005 [Refereed]
     
    Protein adsorption on hydroxyapatite (HAP) thin film was investigated before and after patterning. Hydroxyapatite thin film 100 nm thick was deposited by pulsed laser deposition. The film was patterned by photolithography and wet etching with HCl solution. Proteins (phospholyrase b, bovine serum albumin, and others) labeled with fluorescein isothiocyanate (FITC) were used as the reagent. After the HAP film was soaked in the reagent and washed with pure water, a conspicuous contrast in FITC was observed between the HAP pattern and the glass substrate (or photoresist). This behavior showed that the biocompatibility of the HAP thin film was not influenced by the patterning process. Our technique for HAP thin film is adaptable for applications involving biosensors as electronic devices and scaffolds for tissue culture.
  • M Kusunoki; H Nishikawa; S Hontsu
    PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS ELSEVIER SCIENCE BV 412 1524 - 1527 0921-4534 2004/10 [Refereed]
     
    An error in surface resistance (R-s) originating from the dielectric loss (tan delta) of the parallel plate dielectric resonator using the two-resonators method is investigated. In the two-resonators method, the error in R-s(DeltaR(s)) due to the difference in tan delta(Delta tan delta) between the TE011 and TE01n mode rods is examined, considering the actual scattering of values of tan delta among sapphire rods. Taking this scattering into account, the projected value of DeltaR(s) cannot be disregarded for general R-s values (about 0.1 mOmega) of HTS films. As a comparative simulation, the case of a single resonator was also considered where the tan delta is neglected in the estimate of R-s. Due to the uncertainty and complexity in the two-resonators method, this method is not so superior to the single-rod resonator measurement by neglecting tan 6 at higher resonance frequency. (C) 2004 Elsevier B.V. All rights reserved.
  • S Hontsu; S Mine; H Nishikawa; M Nakamori; A Fujimaki; T Kawai
    SUPERCONDUCTOR SCIENCE & TECHNOLOGY IOP PUBLISHING LTD 17 (5) S255 - S258 0953-2048 2004/05 [Refereed]
     
    We have proposed a novel type of tunable superconducting microwave filter consisting of planar lumped elements which can independently change their centre frequency, bandwidth and skirt characteristics. The independent control is realized by applying the technique of mechanical tuning to the interdigital capacitors C which constitute the filter. We design a three-pole Chebyshev band-pass filter (BPF) with a centre frequency of 6 GHz, 3 dB fractional bandwidth (FBW) of 1.67% and passband ripple of 0.1 dB. The values of C and the meander line inductor L element are calculated using an electromagnetic simulator. The designed filter is fabricated using YBa2Cu3O7-delta (YBCO) film deposited on a MgO(100) substrate (10 mm x 10 mm x 0.5 mm). The measured transmission characteristic shows the typical BPF-like frequency dependence. This result is the first report on the planar lumped-element BPF with a high frequency of 6 GHz. Furthermore, the large shift of the centre frequency of the order of a gigahertz is obtained by an experiment in the mechanical tuning method.
  • ハイドロキシアパタイト超薄膜／ロータス型ポーラス金属複合インプラントの作製
    川島将実; 本津茂樹; 西川博昭; 細井美彦; 樋口裕一; 池田輝之; 中嶋英雄
    Orthopaedic Ceramic Implants 22 23 - 27 2003/12 [Refereed]
  • S Hontsu; S Mine; H Nishikawa; M Nakamori; A Fujimaki; M Inoue; A Maehara; T Kawai
    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC 13 (2) 720 - 723 1051-8223 2003/06 [Refereed]
     
    We propose a mechanically tunable superconducting microwave filter based on lumped elements composed of planar meander-line inductors (L) and inter-digital capacitors (C). As the first step, we have designed and evaluated a 3-pole Chebyshev bandpass filters with lumped elements using a circuit simulator. It is found that the center frequency, bandwidth and skirt rejection of the filter can be controlled by changing only the capacitance. The L and C elements values are estimated using an electromagnetic simulator. Furthermore, we have fabricated the inter-digital capacitor designed with the above procedure. We have evaluated change of the C values using mechanical tuning as a step toward a tunable superconducting microwave filter.
  • H Nishikawa; S Hontsu; M Nakamori; H Tabata; T Kawai
    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC 13 (2) 2725 - 2728 1051-8223 2003/06 [Refereed]
     
    The perovskite type ferromagnetic manganite Pr0.8Ca0.2MnO3 (PCMO) buffer layers for superconducting microwave devices were examined in order to allow Al2O3 single crystal to be used as a substrate for YBa2Cu3O7-delta (YBCO) growth and to provide functionality for microwave devices. The use of magnetic buffer layers with YBCO is effective to magnetically controllable superconducting microwave devices. The (0001) surface of the Al2O3 and [113]-oriented YBCO are used in this study due to the similarity of ion configurations at the interface. YBCO grown on the PCMO buffer shows a critical temperature of 87.5 K. The straight line of YBCO grown on the Al2O3 (0001) buffered by the PCMO shows relatively good transmission property with the, insertion loss of less than 0.7 dB below 70 K measured at 2 GHz. These results indicate that PCMO is a suitable magnetic buffer layer for YBCO growth on Al2O3 (0001).
  • S Mine; M Terakago; T Sakatani; S Hontsu; H Nishikawa; A Fujimaki; M Nakamori; H Tabata; T Kawai
    SUPERCONDUCTOR SCIENCE & TECHNOLOGY IOP PUBLISHING LTD 15 (4) 635 - 638 0953-2048 2002/04 [Refereed]
     
    In order to realize superconductive microwave devices with large tuning characteristics, we have studied a mechanically tunable superconductive resonator beneath a dielectric and/or magnetic floating plate (FP) as a first step. The resonator consists of a half-wavelength coplanar waveguide (CPW). The principle of the mechanically tunable method is that variations of the effective permittivity and/or the effective permeability for the microwave waveguide line can be obtained by changing the distance between the resonator and the FP. In computer simulations of electromagnetic fields for the mechanically tunable half-wavelength CPW resonator, we have obtained a large shift of the resonant frequency with a band of 1.75 GHz to 7 GHz (tunability is approximately 25%) using the (La0.3Sr0.7)(Al0.65Ta0.35)O-3 (LSAT) single crystal (dielectric constant (epsilon(r)) = 22.8, loss tangent (tandelta) = 1.7 x 10(-4)) as the FP. Based on the results, we have performed an experiment using a half-wavelength CPW resonator made from YBa2Cu3O7-delta thin film and the LSAT FP. The result shows a drastic resonant frequency shift of approximately 1.36 GHz (tunability is approximately 20%) when the LSAT FP is moved, using an electromagnetic actuator. In this experiment, it is also noted that the insertion loss is quite low, less than 0.8 dB, compared to previous reports for various tunable filters. Moreover, we have also measured the tuning characteristics with a TiO2 single crystal (epsilon(r) = 85.4, tandelta = 2.5 x 10(-4)) as the FP. As a result, we have obtained quite large tuning characteristics of approximately 2 GHz (tunability is approximately 28%).
  • H Nishikawa; S Hontsu; T Sakatani; M Nakamori; M Terakago; S Mine; H Tabata; T Kawai
    SUPERCONDUCTOR SCIENCE & TECHNOLOGY IOP PUBLISHING LTD 15 (1) 170 - 173 0953-2048 2002/01 [Refereed]
     
    The incorporation of magnetic material buffer layers for superconducting microwave devices is examined in order to allow Al2O3 single crystal to be used as a substrate for YBa2Cu3O7-delta (YBCO) growth and to provide functionality for microwave devices. Two magnetic materials are examined; Ni0.35Zn0.65Fe2O4 (NZFO), which is a spinel-type ferrite, and Pr0.8Ca0.2MnO3 (PCMO), a perovskite-type ferromagnetic material. The use of magnetic buffer layers with YBCO is applicable to magnetically controllable superconducting microwave devices. The (0001) surface of the Al2O3 and [113]-oriented YBCO are used in this study due to the similarity of ion configuration at the interface. YBCO grown on Al2O3(0001) buffered with NZFO does not exhibit superconducting behaviour, whereas that grown on the PCMO buffer superconducts at a critical temperature of 87.5 K. This result indicates that PCMO is a suitable magnetic buffer layer for YBCO growth on Al2O3(0001).
  • M Terakago; S Mine; T Sakatani; S Hontsu; H Nishikawa; M Nakamori; H Tabata; T Kawai
    SUPERCONDUCTOR SCIENCE & TECHNOLOGY IOP PUBLISHING LTD 14 (12) 1140 - 1143 0953-2048 2001/12 [Refereed]
     
    Pr1-xCaxMnO3 (PCMO) (x = 0. 15 similar to0.30) has good dielectric and magnetic properties at the microwave band. High-T-c superconductor (HTS)/ferromagnetic PCMO heterostructure has a high potential for superconducting tunable microwave filters and superconducting magnetostatic wave (MSW) devices. In order to demonstrate the preparation possibility of superconducting MSW devices, we investigated the microwave behaviour of YBaCu3O7-delta(YBCO)/PCMO heterostructures fabricated by a pulsed laser deposition technique on (La0.3Sr0.7)(Al0.65Ta0.35)O-3 (100) substrate. We also fabricated superconducting MSW-band elimination filter (BEF) with YBCO/PCMO structure. The MSW-BEF exhibited notch characteristic that is caused by the energy conversion due to the coupling between the MSW mode and the transverse electromagnetic mode. These results suggest that the HTS/PCMO heterostructure is effective for the superconducting MSW application.
  • S Hontsu; T Sakatani; A Fujimaki; H Nishikawa; M Nakamori; T Kawa
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS INST PURE APPLIED PHYSICS 40 (11A) L1148 - L1150 0021-4922 2001/11 [Refereed]
     
    We propose a mechanically tunable superconducting microwave filter using a floating dielectric or magnetic plate which can be displaced by an actuator above the resonator for frequency tuning. We also examine the transmission and tunable characteristics of the mechanically tunable filter numerically and experimentally. The electromagnetic field simulation based on the moment method shows that a large shift in the resonant frequency by about 1.8 GHz is obtained by displacement of the (La0.3Sr0.7)(Al0.65Ta0.35)O-3 [LSAT] floating dielectric plate by 0.1 mm. In the experiment, we obtained a 1.36 GHz shift from the initial center frequency of 7.05 GHz with little increase in the insertion loss by application of an electric voltage to the electromagnetic actuator. These results suggest that the mechanical tuning of superconducting microwave components is useful for optimizing frequency response and for the functioning of RF filter at the front end of the base station receiver of a software-defined radio (SDR).
  • S Hontsu; T Sakatani; H Nishikawa; M Nakamori; A Fujimaki; T Kawai
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS INST PURE APPLIED PHYSICS 40 (10B) L1100 - L1102 0021-4922 2001/10 [Refereed]
     
    Electric and magnetic properties of Pr0.85Ca0.15MnO3 (PCMO) have been investigated in order to apply the material to Superconducting microwave devices. PCMO films are prepared on (100) surfaces of a (La0.3Sr0.7) (Al0.05Ta0.35)O-3 (LSAT) single crystal by a pulsed laser deposition technique. By optimizing the deposition conditions. c-axis oriented PCMO epitaxial films are obtained. The Curie temperature (T-C) of these PCMO films is approximately 130 K. The remanent magnetization and the coercive field for the sample measured at 77 K are about 240 G and 250 Oe. respectively. The relative dielectric constant and loss tangent are significantly decreased below T-C and are about 13 and 6 x 10(-3) at 30 K. respectively. Furthermore, magnetostatic wave (MSW) excitation is observed in a PCMO film by constructing a band elimination filter based oil the MSW mode with YBa2Cu3O7-delta(YBCO)/PCMO heterostructure. These results indicate that PCMO is applicable for magnetic microwave devices including MSW devices with superconducting thin films.
  • ハイドロキシアパタイト薄膜被覆ロータス型ポーラスステンレス鋼インプラントの作製
    本津茂樹; 赤井正哉; 池田輝之; 西川博昭; 細井美彦; 中嶋英雄
    生体材料 19 (5) 161 - 165 2001/10 [Refereed]
  • H Nishikawa; M Kanai; G Szabo; T Kawai
    PHYSICAL REVIEW B AMER PHYSICAL SOC 61 (2) 967 - 973 1098-0121 2000/01 [Refereed]
     
    The time-of-flight distribution and the amount of desorbed monovalent ion were measured for laser ablation of alkaline-earth metals. The experiment is performed using two wavelengths (193-nm ArF excimer laser and 248-nm KrF excimer laser), a fluence of less than 500 mJ/cm(2) and an effective pulse duration of 14-20 ns. Ion desorption occurs at a lower fluence than that predicted by a thermal evaporation model. The relationship between the amount of desorbed ion and the fluence shows highly nonlinear behavior. Based on the obtained results, a model is proposed in which the laser ablation of alkaline-earth metals is caused by the core electron ionization via the multiphoton photochemical process.
  • Shigeki Hontsu; Hiroaki Nishikawa; Harutaka Nakai; Junya Ishii; Masaya Nakamori; Akira Fujimaki; Yasumasa Noguchi; Hitoshi Tabata; Tomoji Kawai
    Superconductor Science and Technology IOP 12 (11) 836 - 839 0953-2048 1999/11 [Refereed]
     
    As candidates for functional layers. 3d transition metal oxides with perovskite structures show some interesting properties, such as ferromagnetism, ferroelectricity and superconductivity. Accordingly, combinations of these properties can be used to create new tunable microwave devices. Ferromagnetic/ferroelectric/superconducting multistructures, such as La0.70Sr0.30MnO3 (LSMO)/Pb(Zr0.52Ti0.48)O3 (PZT)/YBa2Cu3O7-y (YBCO) and YBCO/PZT/LSMO, have been fabricated by ArF excimer laser deposition on LaSrGaO4 (LSGO) [001] and (La0.30Sr0.70)(Al0.65Ta0.35)O3 (LSAT) [001] substrates. The resulting trilayer films have a highly c-axis oriented structure. Epitaxial YBCO films formed on PZT/LSMO//LSAT have a zero-resistance temperature of 87 K. Moreover, D-E and M-H hysteresis loop are observed for the LSMO/PZT/YBCO//LSGO structure using a conventional Sawyer-Tower circuit and a superconducting quantum interference device (SQUID). The remanent polarization and coercive field of the PZT layer are found to be 19 μC cm-2 and 275 kV cm-1 at 70 K, respectively. The remanent magnetic moment and coercive magnetic field are about 2.6 μB/site and 50 Oe respectively at 78 K. Furthermore, the microwave surface resistance (RS) (22 GHz) of the YBCO film in the YBCO/PZT/LSMO structure was 1.32 mΩ at 77 K. These results suggest that LSMO/PZT/YBCO structures are favourable for use in superconducting microwave applications such as tunable phaseshifters and filters.
  • Kawayama, I; JJ Dubowski; H Nishikawa; T Kawai
    APPLIED SURFACE SCIENCE ELSEVIER SCIENCE BV 143 (1-4) 313 - 318 0169-4332 1999/04 [Refereed]
     
    The variation of surface morphology and chemical composition of cleaved surfaces of (001) Bi2Sr2CaCu2O8 (BSCCO) crystals was investigated following irradiation in vacuum with an ArF excimer laser. Results were obtained for laser fluences in the range from 20 to 500 mJ/cm(2). Distinctive surface structures of BSCCO have been observed having a strong correlation with the laser fluence and number of pulses delivered to the site. The development of a relatively smooth surface (delta similar to 20 nm) has been observed for irradiation at 500 mJ/cm(2). The formation of a 'hexatic' micro-structure on the surface of ablated crystals suggests that a two-dimensional phase transition has occurred, At lower laser fluences, rough surfaces (0.05 mu m < delta < 3 mu m) were developed with characteristic pyramids and/or cone-shape islands. The results indicate that surface modification is due to different mechanisms corresponding to the surface temperature being raised by direct laser irradiation and laser heated plasma. (C) 1999 Elsevier Science B.V. All rights reserved.
  • アルカリ土類金属におけるレーザアブレーションのメカニズム及びダイナミクス
    西川博昭; 官文傑; 松本卓也; 金井真樹; 川合知二
    電気学会論文誌C分冊 117 1213 - 1218 1997/09 [Refereed]
  • Hiroaki Nishikawa; Masaki Kanai; Tomoji Kawai
    Journal of Crystal Growth Elsevier 179 (3-4) 467 - 476 0022-0248 1997 [Refereed]
     
    Thin film growth of perovskite-type oxides, CaTiO3 and La0.7Sr0.3MnO3, on atomically smooth SrTiO3(1 0 0) substrate has been studied by in-situ reflection high-energy electron diffraction (RHEED) and ex-situ atomic force microscope (AFM) in order to understand the key points to keep the surface flatness. It is found out that the termination of substrate surface by AO layer of perovskite structure (ABO3), i.e., CaO, SrO and BaO, is quite effective to prepare the atomically flat thin films. Among these top layers, the SrO termination gives the best result. CaTiO3 film on SrTiO3(1 0 0) can keep the atomically flat surface in spite of large lattice mismatch (∼ 2.3%), while La0.7Sr0.3MnO3 needs more strict lattice matching to keep the flat surface. Structure and orientation of SrO are analyzed by only in-situ RHEED observation as the first step of real-time growth control. Furthermore, the migration process of Sr supplied by laser ablation is studied by time-resolved measurement of RHEED intensity. The growth process of thin film by laser ablation method is discussed with this experiment.
  • Hiroaki Nishikawa; Gabor Szabo; Tomoji Kawai
    Japanese Journal of Applied Physics IOP Publishing 35 (Part 2, No. 8A) L985 - L988 0021-4922 1996/08 [Refereed]
     
    We have performed double-pulsed laser ablation experiments on Ca samples with an ArF excimer laser. The amount of desorbed monovalent ions was measured using a quadrupole mass spectrometer as a function of the delay between the laser pulses. In the case of 6 ns delay, the total amount of desorbed ions is decreased to ≈ 0.1 times that with no delay. On the basis of this result, it is discussed that the laser ablation of Ca metal is caused by multiphoton photochemical reaction via a lattice/defect-assisted mechanism.
  • H Nishikawa; M Kanai; T Kawai
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS JAPAN J APPLIED PHYSICS 35 (4A) L425 - L428 0021-4922 1996/04 [Refereed]
     
    The time-of-flight distribution and the amount of desorbed monovalent ions have been measured in the laser ablation of alkaline earth metals. The obtained relationship between the amount of ions and the laser fluence indicates that the desorption is caused by 5-, 4- and 3-photon processes for Ca, Sr and Ba, respectively when an ArF excimer laser is used as a light source. On the basis of the results, a model is proposed in which the laser ablation of the alkaline earth metals is triggered by excitation of the core electrons at the highest energy level.
  • T Kawai; H Nishikawa; K Koguchi; M Kanai
    ADVANCED LASER PROCESSING OF MATERIALS - FUNDAMENTALS AND APPLICATIONS MATERIALS RESEARCH SOC 397 169 - 174 0272-9172 1996 [Refereed]
  • H NISHIKAWA; M KANAI; T KAWAI; S KAWAI
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS JAPAN J APPLIED PHYSICS 33 (8A) L1090 - L1092 0021-4922 1994/08 [Refereed]
     
    In order to investigate the laser ablation mechanism, the velocity distribution and amount of Sr+ produced by ArF excimer laser irradiation of Sr metal have been measured by time-of-flight (TOF) mass spectroscopy. The velocity distribution of Sr+ agrees with the Maxwell-Boltzmann distribution corrected by the center-of-mass velocity. The relationship between the amount of produced ions and laser fluence suggests that Sr+ is produced by a 4-photon process. Based on these experimental results, a simple model for the laser ablation mechanism of Sr metal is proposed.

Books etc

  • 最新実用真空技術総覧編集委員会 (Contributor第2部第3編第5章 パルスレーザ蒸着(PLD))エヌ・ティー・エス 2019/02 9784860435592 vi, 23, 37-1084, 11p
  • Correlated Functional Oxides: Nanocomposites and Heterostructures
    H. Nishikawa; N. Iwata; T. Endo; Y. Takamura; G.-H. Lee; P. Mele (ContributorAtomic Processes of Pulsed Laser Deposition During Growth of Alkaline Earth Oxide Thin Films)Springer 2016/11 9783319437774 232 205-230
  • Nanocomposites, Nanostructures and Heterostructures of Correlated Oxide Systems
    T. Endo; H. Nishikawa; N. Iwata; A. Bhattacharya; L. W. Martin (Joint editor)Materials Research Society 2012/10 9781605114316
  • 持ちつ持たれつ 生き物とエレクトロニクス
    吉川昭; 中迫昇; 本津茂樹; 長江貞彦; 浅居正充; 中桐紘治; 秋濃俊郎; 堀江和夫; 西川博昭; 楠正暢 (Joint work第5章「現代の錬金術―オーダーメイド物質」)電気書院 2006/08 448530017X
  • Porous Metals and Metal Foaming Technology
    H. Nishikawa; T. Hayami; S. Hontsu; M. Kusunoki (Joint workAddition of Advanced Biocompatibility to a Porous Artificial Root, p.59-p.62)日本金属学会 2006/02 4889034056
  • レーザアブレーションとその応用
    堀田和明; 緑川克美; 西川博昭 (Contributor第2章第3節「金属のレーザアブレーション」p.26-p.33)コロナ社 1999/11 9784339007152

MISC

Industrial Property Rights

  • 特願2020-028250:フレキシブルセラミックス素子およびその製造方法  2020年/02/21
    西川博昭, 馬谷真司  近畿大学
  • 特開2013-122073:薄膜形成装置  2013/06/20
    本津茂樹, 西川博昭, 楠正暢, 吉川一志, 山本一世
  • 特許5214009:生体親和性透明シート、その製造方法、及び細胞シート    2013/03/08
    本津茂樹, 西川博昭, 楠正暢, 畑中良太
  • 特開2012-249570:生体親和性透明シート、その製造方法、及び細胞シート  2012/12/10
    楠正暢, 西川博昭, 本津茂樹, 松田太陽
  • 特許5110559:被覆ステント    2012/10/19
    本津茂樹, 西川博昭, 楠正暢, 畑中良太
  • 特許4919519:生体親和性透明シート、その製造方法、及び細胞シート    2012/02/10
    本津茂樹, 西川博昭, 楠正暢, 畑中良太
  • 特許4670084:化学センサ装置用の検出子およびその利用    2011/01/28
    本津茂樹, 楠正暢, 西川博昭, 橋本典也, 山田泉
  • 特許4585790:細胞培養足場および細胞培養方法    2010/09/10
    本津茂樹, 楠正暢, 西川博昭  
    特許公開2005-278609
  • 特許4522822:高生体親和性を持つ多孔質インプラント及びその製造方法    2010/06/04
    本津茂樹, 速水尚, 西川博昭, 楠正暢, 川島将実  
    特許公開2006-136457
  • 特開2009-201639:インプラント  2009/09/10
    本津茂樹, 楠正暢, 西川博昭, 三舩英雄
  • 特許4328664:化学バイオセンサおよびその製造方法    2009/06/19
    本津茂樹, 西川博昭, 楠正暢  
    特許公開2005-283550
  • 特開2002-64312:電磁波素子  2002/02/28
    本津茂樹, 西川博昭, 藤巻朗, 川合知二, 酒谷知孝  
    特許公開2002-64312
  • 特開2001-36155:電磁波素子  2001/02/09
    本津茂樹, 西川博昭, 石井順也, 仲森昌也, 藤巻朗, 田畑仁, 川合知二  
    特許公開2001-36155

Awards & Honors

  • 2015/10 The 14th International Union of Materials Research Societies-International Conference on Advanced Materials Best Poster Award
     Effect of concentration and pH of buffered phosphoric acid aqueous solution to surface nanostructures of Al2O3 (0001) 
    受賞者: A. Saito;T. Tsunemine;T. Makino;M. Kusunoki;H. Nishikawa
  • 2014/10 日本歯科保存学会 カボデンタル優秀ポスター賞
     Er: YAGレーザー成膜法による歯質上へのアパタイト膜の直接形成 
    受賞者: 本津茂樹;山本衛;加藤暢宏;西川博昭;吉川一志;山本一世
  • 2001/06 The 8th International Superconductive Electronics Conference Excellent Poster Award
     Tuning Characteristics of Mechanically Tunable Superconducting Microwave Filter 
    受賞者: S. Mine;M. Terakago;T. Sakatani;S. Hontsu;H. Nishikawa;A. Fujimaki;M. Nakamori;H. Tabata;T. Kawai

Research Grants & Projects

Committee Membership

  • 2017/09 -2018/10   The 4th European-MRS & MRS-Japan Bilateral Symposia   Organizer

Other link

researchmap


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