J c , * Characterization of Local J c Distribution in Superconducting Wires and Tapes Based on Scanning Hall-probe Microscopy Kohei HIGASHIKAWA *,,

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1 J c *, * * Characterization of Local J c Distribution in Superconducting Wires and Tapes Based on Scanning Hall-probe Microscop Kohei HIGASHIKAWA *,, Masaoshi INOUE * and Taanobu KISS * Snopsis: This article reviews a method for characterizing the local critical current densit (J c ) distribution in superconducting tapes and wires based on scanning Hall-probe microscop (SHPM). This method is ver powerful for (1) finding the bottlenec that limits the global performance of a superconductor, () investigating the local inhomogeneit that ma become the origin of local quench, especiall in HTS applications, () establishing the processes for narrow and/or multifilamentar HTS conductors for reducing the magnetization in magnet applications and the AC losses in power applications. The principle and the functions of this technique are introduced b referring to characterization eamples of REBCO coated conductors and an MgB wire. Kewords: scanning Hall-probe microscop, critical current densit distribution, local homogeneit, HTS tape, MgB wire J c J c 1 μv/cm I c SQUID J c Received Jul, 14 * Kushu Universit, Graduate School of ISEE 744 Motooa, Nishi-u, Fuuoa , Japan ohei@super.ees.ushu-u.ac.jp DOI : 1.1/jcsj J c J c J c cmμm RE-1 J c

2 J c SHPM J c Fig. 1 J c J c 1) J c J c Current flow Magnetic field Fig. 1 Schematic diagrams of current flows in shielding state and in remanent state. These currents flow at critical current densit according to the critical state model. z J r (,,) J B z r(,,z) Fig. Illustration of the relationship between the perpendicular component of the magnetic field, B z, measured at a position above a film, r(,, z), and the sheet current densit vector, J(J, J ), at a position in the film, r (,, ). J c Biot-Savart ( r ) ( r r ) J d B() r = μ d r (1) 4π r r r r B J d μ Fig. d (1) ) B z (,, z) (, )( ) ( ) J ( ) μ + + J, () = d d 4π ( ) + ( ) + z ) (,, z) r (,, z ) r B z B (J, J ) J=J d d () (, ) () ) μ z () b ( ) = ( ) ( ) z,, z i e j, j, b z B z j, J, i j j 1 J = (, ) i j (, ) = i j (4) ()(4)j j ) z i e (, ) = b ( ) j z, μ z i e (, ) = b ( ) j z, μ (5) (6) z b z 486 TEION KOGAKUJ. Cro. Super. Soc. Jpn.Vol. 49 No. 914

3 1 1 Be = 15 mt ࡇࡇ ὀពࡍ ࡁⅬ ࠊ㧗㛫 Ἴ ᡂศ ቑᖜ ࡀ ࡁ ࡇ ࠊ ィ㞧㡢 ቑᖜࡉ ࡋ ࡇ ࠋᚑࡗ ࠊ㞧㡢 ᮶ 㛫㧗ㄪἼᡂศ ษ ᤞ ᚲせࡀ ࠊලయ ḟᘧ ࡍ ࢫ ࢱ 㐺 ࡍ ࡇ ࠋ ) π 1 + cos cut -off ¹ w( ) = for cut -off ࠉ for > cut -off - Measured magnetic field Bz (T) (7) (8) Be = 9 mt Be = 75 mt Be = 6 mt Be = 45 mt 4 1- Be = mt Be = 18 mt - 1 Be = 9 mt Be = mt Be = mt after 1 mt ࡓࡔࡋࠊcut-off Ἴ ࠊࡇ ᑐᛂࡍ ࠋ ᚋ ࠊ ኚ ࡇ ࠊᐇ 㛫㠃ෆ㟁ὶᐦᗘ ࢡ J(J, J)ࡀồ ࠋ ௨ ࠊ ᙧ ヨホ౯ ࡀࠊཌࡉࡀ ࡁ ࡃࠊཌࡉ᪉ 㟁ὶศᕸ ホ౯ࡍ ᚲせࡀ ሙ ࠊ ᆶ ᡂศ ࡃࠊᖹ ᡂศ ィ ࡍ ᚲせ Be = 15 mt - Be = 9 mt Be = 75 mt Be = 6 mt Be = 45 mt 4 1- Be = mt Be = 18 mt - Be = 9 mt 1 Be = mt B = mt e after 1 mt ࡀ ࠋ ࡓࠊホ౯ 㛫 ᛶయࡀ ሙ ࠊゎ -8 ᯒ ゎࡃࡇ ᅔ㞴 ࠊ ゎᯒ ウ ࠋ ௨ ཎ ࠊ ᰝᆺ Ꮚ㢧ᚤ㙾㸦SHPM㸧 ࡗ ሗࡀᚓ ࠊ ࡎ REBCO ࡓホ౯ ࡍ ࠋFig. ᐃ ࡓ SHPM ᴫ ᅗ ࡍࠋᾮయ ࢱ ࢡ እ㒊 ༳ຍ Bi- ࢥ ࡀタ ࡉ ࠊヨ ࡑ ෆ タ ࡉ ࠋ ࠊࢥ ヨ ᪉ ᾮయ ࢱ ࢡ ఏᑟ ࡗ ෭ ࡉ ࠊ ᆺ ヨ ᗘ 79 K ࠋ ࡓࠊ1 mt እ㒊 ༳ຍࡍ ࡇ ࡀ ࡗ ࠋヨ ࢡ ࡁࡉࡀ 5 ࢡ ゅ ࢭ ࢧࡀ ࠊ ᐦ ࢫ ࢪ ࡗ ᰝࡍ ࡇ ࡀ ࡁ ࠋ ࠊィヨ ࢧ ࢬ 8 mm mm ᗘ ࠊヨ (mm) 6 1 Sheet current densit J (A/m) ᐃ᪉ἲ Ἴ㛗λcut-off ࡀᮏホ౯ᡭἲ 㛫ศゎ Ỵᐃࡍ 5( ᑻヨ ࡓホ౯ 6 (mm) In-plane magnetic field Bz (T) bz (, ) = bz (,,) = e z bz (,, z ) Be = 15 mt 4 1 Be = 9 mt Be = 75 mt 1 Be = 6 mt Be = 45 mt Be = mt Be = 18 mt - 1 Be = 9 mt Be = mt -4 1 Be = mt after 1 mt (mm) Fig. 4 Eperimental results for a 1-mm-wide short sample of IBAD-PLD GdBCO coated conductor eposed to different conditions of eternal magnetic fields: lateral distributions of measured magnetic field, magnetic field in the plane, and longitudinal component of sheet current densit, b onedimensional scanning ). A 㟁ὶ 㟁 ࡁ 㟁ὶ ഛ ࠋ እ㒊 ༳ຍ 㟁 ᮏホ౯ ࠊIBAD-PLD ἲ ࡗ స〇ࡉ ࡓ Eternal magnetic field: < 1 mt Tpical stage temperature: 79 K Active area of Hall sensor: 5 μm square Spatial step: 1 μm in,,.5 μm in z Current leads GdBCO ᑻヨ㸦ᖜ 1 mmࠊ㛗ࡉ mm㸧ホ౯ ࡗࡓࠋ ఏᑟ ෭ ࡋࡓヨ ᑐࡋ ࠊእ㒊 Hall sensor Observation window Bi- coil with Cu bobbin ༳ຍࡋࡓ㝿ホ౯ ᯝ Fig. 4 ࡍࠋ ᅗ 1 ḟ Sample AlN plate z ඖ ᰝ ࡗ ᚓ ࡓヨ ᖜ᪉ ศᕸ ࡋ ࡀࠊእ㒊 ቑຍࡉࡏ ࡋࡓࡀࡗ ࠊヨ ෆ ࡀ ෆ㒊 ධࡋ ࡃᵝᏊࡀ ど ࡉ ࠋFig. 4 ヨ 17 μm ࡍ ࢭ ࢧ ᐃࡋࡓ ศ LN outlet ᕸ ࡋ ࡀࠊᘧ(7) ࡗ Fig. 4 ࡍ ヨ LN tan LN inlet 㠃ෆ ࡍ ࡇ ࠊࡑ ᵝᏊࡀ Scanning Hall-probe microscop ) Fig. Photograph and schematic diagram of a SHPM sstem. ప ᕤᏛ 49 ᕳ 9 14 ᖺ ࠋ ࡓࠊFig. 4 ࠊࡑ ศᕸ ᑐᛂࡍ ࢩ 487

4 J c 6 mt J c 6 mt 1 mt Fig. 4 J c J c J c Fig. 5 Fig. 51 Farada Fig. 6 J c 1-9 V/m 1-4 V/m J c Fig. 7 Fig. 7 Fig. 7 Fig. 7(d)(e) Fig. 7(e) J c Fig. 7 J c Fig. 7(e) J c Fig. 7(f) mt Fig. 7(g) J c J c J c Measured magnetic field B z (T) Measured magnetic field B z (T) st scan nd scan st scan nd scan blown up to (mm) (mm) Fig. 5 Magnetic relaation at the remanent state. The time interval between the 1 st and nd scans was s 4). is a blow up of a region shown in 4). Electric field E (V/m) (mm) Fig. 6 Electric field induced b the magnetic relaation 4). 488 TEION KOGAKUJ. Cro. Super. Soc. Jpn.Vol. 49 No. 914

Measured magnetic field B z (mt) Sheet current densit J (A/mm) Sheet current densit J (A/mm) Sheet current densit J (A/mm) 5 15-5 -5 5-5 5 5 B z 6 J J (d) J (e) Spatial inhomogeneit & J c (B)

5 mm = -1.5 mm = -.5 mm = -.5 mm = -4.5 mm J c (B). 1-1 - 1-1 In-plane magnetic field B z (T) Spatial inhomogeneit Fig.

5 Measured magnetic field B z (mt) Sheet current densit J (A/mm) Sheet current densit J (A/mm) Sheet current densit J (A/mm) B z 6 J J (d) J (e) Spatial inhomogeneit & J c (B) In-plane magnetic field B z (mt) Critical sheet current densit J c ( mt) (A/mm) 15-1 mm 4 1 B z (f) J c (g) Normalized sheet current densit J (A/m) = 4.5 mm =.5 mm =.5 mm = 1.5 mm =.5 mm = -.5 mm = -1.5 mm = -.5 mm = -.5 mm = -4.5 mm J c (B) In-plane magnetic field B z (T) Spatial inhomogeneit Fig. 7 Measurement results for a piece of 1-mm-wide GdBCO coated conductor fabricated using IBAD-PLD processes and visualized b scanning Hall-probe microscop: measured magnetic field at the Hall sensor perpendicular to the sample, B z, magnetic field estimated at the superconducting laer, B z, longitudinal component of sheet current densit, J, (d) width component of sheet current densit, J, (e) absolute value of sheet current densit, J, (f) sheet current densit normalized at B z = mt, J n, as a function of B z obtained for 1 different positions on the arrow in (e), and (g) critical sheet current densit, J c, estimated at B z = mt. The arrow in indicates the location for the magnetic relaation measurement, 5). Sheet current densit J Sheet current densit J =. w =.1 w =. w =. w =.4 w =.5 w =. w =.1 w =. w =. w =.4 w =.5 w Fig. 8 Lateral distributions of sheet current densities and their absolute values in remanent states, where I c and w are the critical current and the width of a coated conductor, respectivel 6). The positions where J =.5 I c / w matches with the edges of the conductor independent of the value of cut-off wavelength,, of the distributions 6). The equivalent width, w e, can be determined b the distance between such positions. Total sheet current Cut-off wavelength Fig. 9 Relationship between the total sheet current, I, (the area of the lateral distributions shown in Fig. 8) and their cut-off wavelength,, where I c and w are the critical current and the width of a coated conductor, respectivel 6). J c Fig. 8 Fig. 8 J c I c

6 w Laser slit (copper coating) Mechanical slit Fig. 9 I c w I = J d < w w c for λcut-off.6λ cut-off (9) Fig. 8 I c w w e J c I c Fig. 1 5 mm 5 Fig. 1 Fig. 1 I c Critical sheet current densit J c,mt (A/mm) Critical current I (A) c,mt Equivalent width w (mm) e J c 1 mm Longitudinal position (mm) Longitudinal position (mm) filament_1-5 filament_1-4 filament_1- filament_1- filament_1-1 filament_1-5 filament_1-4 filament_1- filament_1- filament_1-1 Fig. 1 Eperimental results for 5-mm-wide 5-filamentar coated conductor: critical current densit distributions obtained for two pieces, local critical current for each filament and equivalent width for each filament in the upper piece 7). Side of stabilizer Side of substrate Equivalent width w e (mm) Irradiated from substrate Irradiated from substrate Irradiated from stabilizer SC laer bent to substrate SC laer bent to stabilizer 1 (d) 4 (e) 5 (f) 6 Sample Fig. 11 Difference in the equivalent width for the samples slit b different cutting methods 6). Micrographs of the cross-section near the edge of the samples are also shown in the figure. The micrographs for samples - were taen after copper coating that was done after slitting. The error bar in the equivalent width indicates the standard deviation for each sample estimated from the longitudinal distribution 6). Fig. 11 mm J c I c RTR-SHPMFig. 1 1 m mm m/h 4 1 mm 8) 49 TEION KOGAKUJ. Cro. Super. Soc. Jpn.Vol. 49 No. 914

7 Fig. 1 ホ౯ ࡍࠋホ౯ᑐ ࡋࡓヨ ࠊIBAD- PLD ᇶᯈ స〇ࡉ ࡓ GdBCO ࠊ MOD 㻴㼕㼓㼔㻙㼟㼜㼑㼑㼐㼟㼠㼍㼓㼑㻌㼒㼛㼞㼟㼏㼍㼚㼚㼕㼚㼓㻌㼍㻴㼍㼘㼘㻌㼜㼞㼛㼎㼑 PLD ヨస PLD ᯝ ࡋ ࠋᒁᡤ Ic ศᕸ ࡘࡁ 㡰 ᑠࡉ ࡇ ࡀ ࡗ ࡀࠊࡇ せᅉ ど ࡍ ࡇ ᡂ ࡋ ࠋ ࠊ.5 m ᮇ mm ᮇ ᖜ᪉ ➃㒊 ᛶࡀప ࡋ ࠊࡇ ࡀ グ ࡘ 㻾㼑㼑㼘㻙㼠㼛㻙㼞㼑㼑㼘㼍㼜㼜㼍㼞㼍㼠㼡㼟㻌㼒㼛㼞㼏㼍㼞㼞㼥㼕㼚㼓㼏㼛㼍㼠㼑㼐㼏㼛㼚㼐㼡㼏㼠㼛㼞 ࡁ ཎᅉ ࡗ ࠋ ࠊ15 mm ᮇ ศ ᮇ ᛶప 㒊ࡀぢ ࠊࡑ ࡀせᅉ ࡇ ࡀ ࡗࡓࠋ ᪉ࠊ 㛵ࡋ ࠊ㠃ෆ 㧗ᆒ ᛶࡀᚓ ࡇ ࡗࡓࠋ ࡇ ࠊ༢ Ic ศᕸ ࡃࠊࡑ ཎᅉ 㠃ෆ ᆒ ᛶ ࡗ ㄽࡍ ࡇ ࡀ ࠋ ࡓࠊࡇ ḟඖ 㠃ෆᆒ ᛶ ሗ ࠊ ᚋ ࡅࡓ㧗ᆒ స〇ࠊ ࡑ ຍᕤᚋ ရ ࡁ ጾຊ ࡍ ࠋ Hall-probe scanning in width direction Conductor carring in longitudinal direction Fig. 1 Reel-to-reel scanning Hall-probe microscop (RTRSHPM) sstem: photograph and scanning method 9). 4 5 mm 1m 66 5 mm 1m 6 5 mm Sheet current densit 5 mm J (A/mm) 1 mm 4 1m Fig. 1 In-plane distribution of local critical current densit in 1-m-long pieces of coated conductors (CCs): MOD CC, commercial PLD CC, and R&D PLD CC 1). ప ఏᑟ ホ౯ ᒎ㛤 ௨ ウ ࠊᾮయ ᗘ ᑐ ࡋࡓ ࡀࠊ MgB 11, 1) ᚋ ᒎ㛤ࡀᮇᚅࡉ 㕲 ఏᑟయ 1) ࡉ ࡇ ㄆࡋ ࠋᮏ ሙ ࠊᒁᡤ ࡑ ಸ ᗘ ࢩ ࡋ 㒊 ࡀᏑ ᅾࡋ ࠋ ࠊ㟁ὶไ㝈ᅉᏊ ゎ ࡁ ᛶ 㣕 ࡘ ࡀ ࠋࡑࡇ ࠊᒁᡤ Ic ప 㒊ホ౯ ࠊFig. 14 ࡍ ప ᰝᆺ ᐃࡋࡓ ࠊ㟁Ꮚ㢧ᚤ㙾ほᐹ ࡑ Ꮚ㢧ᚤ㙾㛤 ࡋ ࠋᮏࢩࢫ ࠊ せᅉ ㄪ ࡓࠋࡑ ᯝ Fig. 16 ࡍࠋṧ ෭ ࡗ ෭ ࢫ ࢪ ᗘ 5 K ไᚚࡍ ప 㒊 ᒁᡤḞ㝗ࡀ ࡇ ࡀண ࡉ ࡀࠊࡑ ࡇ ࡀ ࡗ ࠊ ࡓ ఏᑟ ࢢ ᗘ ᯒฟ ࡀほ ࡉ ࠊඖ ศᯒ ᯝ Mg Si ࡏ ࡇ 5 T እ㒊 ༳ຍࡍ ࡇ ࡀ ಙ ࡀ ฟࡉ ࡓࠋࡇ ᯒฟ MgSi ࠊC ࡗ ࠋ ᛶ ࡗ ῧຍࡋࡓ SiC ᮶ ෆ㒊 Mg ᣑᩓἲ ࡗ స〇ࡉ ࡓከⰺ ホ౯ ᯒฟ ࡀ ᛶไ㝈ᅉᏊ ࡗ Ỵᐃ ドᣐ ࡘ Fig. 15 ࡍࠋᮏヨ ࠊࡇ ᙧ ࡇ ࡀ ࡁࡓࠋᐇ㝿 ࠊ ᅾ C ἲ ࡗ ࡃ ࡓ ཌࡉ᪉ ᆒ ᛶ ௬ᐃࡋ ࡅ ᛶ 㣕 ࡋ ࠋࡇ ࠊᵝࠎ ࡀࠊṧ ศᕸ ࡑ ࡒ ᒁ ඛ㐍 ఏᑟ ᑐࡋ ࠊࡑ ᛶไ㝈ᅉᏊ ゎ ᡤ Ic ศᕸ ホ౯ࡍ ࡇ ࡀ ࡁ ࠋ ࡓࠊᒁᡤ ᑠ ࡀ ഛࡀ ࡗ ࠋ Ic ࡗ ᅄ➃Ꮚἲ ࡗ ᚓ Ic ࡀไ㝈 ࠉప ᕤᏛ 49 ᕳ 9 14 ᖺ 491

Superconducting magnet Low-Temperature Scanning Hall-Probe Microscope (LT-SHPM) Specifications Eternal magnetic field: -5 T Stage temperature: 5-1 K Scanning range: 1 1 mm Horizontal scanning

1 I c / I c_ave Measured magnetic field B z (mt) -4 5 14 B z Polished sample for the SHPM measurement Filament U Filament M Filament L Considering the proportional relationship between B z and I c

15 Longitudinal variation of local critical current in each filament of a multifilamentar MgB wire estimated from remanent magnetic field distribution measured using scanning Hall-probe microscop

16 Comparison between remanent magnetic field distribution measured b SHPM and SEM image. EDS elemental mappings are also shown for Mg and (d) Si 1).

8 Superconducting magnet Low-Temperature Scanning Hall-Probe Microscope (LT-SHPM) Specifications Eternal magnetic field: -5 T Stage temperature: 5-1 K Scanning range: 1 1 mm Horizontal scanning resolution:.5 μm Vertical scanning resolution:.5 μm Active area of Hall sensor: 5 5 μm Sample Sample stage Hall sensor Mirror Fig. 14 Low-temperature scanning Hall-probe microscope (LT- SHPM). 1 I c / I c_ave Measured magnetic field B z (mt) B z Polished sample for the SHPM measurement Filament U Filament M Filament L Considering the proportional relationship between B z and I c sheath MgB bore Filament U Filament M Filament L.5 mm Fig. 15 Longitudinal variation of local critical current in each filament of a multifilamentar MgB wire estimated from remanent magnetic field distribution measured using scanning Hall-probe microscop (SHPM) at 1 K 1). Trapped fields come from upper (U) and lower (L) filaments as well as from the central filament (M) 1). Remanent magnetic field B z (mt) B z Mg SEM.1 mm Fig. 16 Comparison between remanent magnetic field distribution measured b SHPM and SEM image. EDS elemental mappings are also shown for Mg and (d) Si 1). Si (d) U M L SHPM J c NEDO JST ALCA MgB JST S- JST SUPER- IRON: 1) E.H. Brandt and M. Indenbom: Tpe-II-superconductor strip with current in a perpendicular magnetic field, Phs. Rev. B 48 (199) ) B.J. Roth, N.G. Sepulveda and J.P. Wiswo Jr: Using a magnetometer to image a two-dimensional current distribution, J. Appl. Phs. 65 (1989) 61-7 ) K. Higashiawa, M. Inoue, T. Kawaguchi, K. Shiohara, K. Imamura, T. Kiss, Y. Iijima, K. Kaimoto, T. Saitoh and T. Izumi: Scanning Hall-probe microscop sstem for two-dimensional imaging of critical current densit in RE-1 coated conductors, Phsica C 471 (11) ) K. Shiohara, K. Higashiawa, M. Inoue, T. Kiss, Y. Iijima, T. Saitoh, M. Yoshizumi and T. Izumi: Measurement of in-plane magnetic relaation in RE-1 coated conductors b use of scanning Hall probe microscop, Phsica C 484 (1) ) K. Higashiawa, K. Shiohara, M. Inoue, T. Kiss, M. Yoshizumi and T. Izumi: Estimation of local current transport properties in thin film superconductor based on scanning Hall-probe microscop, MRS Proceedings 144 (1) mrss1-144-i-4 6) K. Higashiawa, K. Katahira, K. Oumura, K. Shiohara, M. Inoue, T. Kiss, Y. Shingai, M. Konishi, K. Ohmatsu, M. Yoshizumi, T. Izumi and H. Oamoto: Lateral distribution of critical current densit in coated conductors slit b different cutting methods, IEEE Trans. Appl. Supercond. () (1) TEION KOGAKUJ. Cro. Super. Soc. Jpn.Vol. 49 No. 914

9 7) K. Higashiawa, K. Shiohara, M. Inoue, T. Kiss, T. Machi, N. Chiumoto, S. Lee, K. Tanabe, T. Izumi and H. Oamoto: Noncontact characterization of in-plane distribution of critical current densit in multifilamentar coated conductor, IEEE Trans. Appl. Supercond. () (1) ) K. Higashiawa, K. Shiohara, Y. Komai, K. Oumura, K. Imamura, M. Inoue, T. Kiss, Y. Iijima, T. Saitoh, T. Machi, M. Yoshizumi, T. Izumi and H. Oamoto: High-speed scanning Hallprobe microscop for two-dimensional characterization of local critical current densit in long-length coated conductor, Phsics Procedia 7 (1) 8-1 9) K. Higashiawa, K. Katahira, M. Inoue, T. Kiss, Y. Shingai, M. Konishi, K. Ohmatsu, T. Machi, M. Yoshizumi, T. Izumi and Y. Shiohara: Nondestructive diagnostics of narrow coated conductors for electric power applications, IEEE Trans. Appl. Supercond. 4 () (14) ) T. Kiss, et al.: Spatial frequenc analsis on local critical current distribution in REBCO coated conductors, Abstract of 75th autumn meeting of JSAP (14) in press REBCO (14) in press 11) K. Higashiawa, A. Yamamoto, T. Kiss, S. Ye, A. Matsumoto and H. Kumaura: Magnetic microscop for characterization of local critical current in iron-sheathed MgB wires, Phsica C 5 (14) ) K. Higashiawa, et al.: Local critical current and its relationship with microstructure in MgB wires fabricated b internal Mg diffusion process, Abstracts of CSSJ Conference 87 (1) 98 Mg MgB 87 1 (1) 98 1) V. Braccini, S. Kawale, E. Reich, E. Bellingeri, L. Pellegrino, A. Sala, M. Putti, K. Higashiawa, T. Kiss, B. Holzapfel and C. Ferdeghini: Highl effective and isotropic pinning in epitaial Fe(Se,Te) thin films grown on CaF substrates, Appl. Phs. Lett. 1 (1) PD Wisconsin Twente 6 IEEEMRSACerS

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< BDF91E58E9F90A291E38AEE94D595F18D908F E696E6464> 近畿大学次世代基盤技術研究所報告 Vol. 9(2018)55-59 Additive Manufacturing *1 *2 *3 The Recent Trend on Additive Manufacturing Technology: A Review Hideki KYOGOKU *1, Toshi-Taka IKESHOJI, Makiko YONEHARA The recent trend