４．超伝導線材の研究開発

国立研究開発法人物質・材料研究機構
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超伝導線材の研究開発
１

はじめに……………………………………………………………………………………………………… ４−１２合金系線材（Nb-Ti）………………………………………………………………………………………… ４−１

３

A15型化合物系線材 ………………………………………………………………………………………… ４−３

３．１

Nb3Sn線材 …………………………………………………………………………………………… ４−３

３．２

Nb3Al線材 …………………………………………………………………………………………… ４−６４銅酸化物系線材……………………………………………………………………………………………… ４−９４．１

Bi系線材（Bi-2212及びBi-2223）…………………………………………………………………… ４−９４．２

希土類系線材（RE-123）……………………………………………………………………………… ４−11５

MgB2線材 …………………………………………………………………………………………………… ４−12６

鉄系線材……………………………………………………………………………………………………… ４−15

参考文献………………………………………………………………………………………………………… ４−15

MgB2ࠊյ㕲⣔ࡢ㸳ࡘ࡟኱ูࡉࢀࡿࠋᮏㅮ⩏ࡢ๓༙㉸ఏᑟ⥺ᮦࡢ◊✲㛤Ⓨ

㸦I㸧࡛ࡣࠊᐇ⏝⥺ᮦ࡜ࡋ࡚⌧ᅾࡢ㉸ఏᑟᛂ⏝ࢆᢸ࠸ࡘࡘࡶᆅ㐨࡞◊✲㛤Ⓨࡀ㐍ࡵࡽࢀ࡚࠸ࡿձྜ

1. ࡣࡌࡵ࡟

㔠⣔㸦Nb-Ti㸧ཬࡧղA15 ᆺ໬ྜ≀⣔㸦Nb3Snࠊ

௒᪥ࠊMRI ࡸ NMRࠊ㧗࢚ࢿࣝࢠ࣮⢏Ꮚຍ㏿ჾ

Nb3Al㸧⥺ᮦ࡟ࡘ࠸࡚ࠊᚋ༙㸦II㸧࡛ࡣ㧗࠸ Tc ࡸ࡞࡝࡟ᐇ⿦ࡉࢀ࡚࠸ࡿᐇ⏝㉸ఏᑟ⥺ᮦࡢ኱㒊ศ

Bc2 ࢆᣢࡕᐇ⏝໬ࡀᮇᚅࡉࢀࡿճ㖡㓟໬≀⣔ࡣྜ㔠⣔ࡢ Nb-Ti ⥺ᮦ࡛࠶ࡾࠊࡑࡢඃࢀࡓᒎᘏᛶ

㸦RE-123ࠊBi-2212 ཬࡧ Bi-2223㸧
ࠊմMgB2 ཬࡧ࡜ࣁࣥࢻࣜࣥࢢࡢⰋࡉ࡟⏤᮶ࡍࡿࠋ㧗☢ሙ NMRյ㕲⣔⥺ᮦ࡟ࡘ࠸࡚ࠊࡑࢀࡒࢀࡢᮦᩱᏛⓗ≉ᚩ࡜ࡢෆᒙࢥ࢖ࣝ࡞࡝ࠊNb-Ti ⥺ᮦ࡛⿵࠼࡞࠸㧗☢ሙ㉸ఏᑟ≉ᛶࠊᵝࠎ࡞⥺ᮦ໬ࣉࣟࢭࢫ࡜ࡑࢀࡽࡢ㛗⏝࡟ࡣ A15 ᆺ໬ྜ≀㉸ఏᑟయ࡛࠶ࡿ Nb3Sn ⥺ᮦᡤࡸ▷ᡤࠊ௒ᚋࡢ㛤Ⓨㄢ㢟ࡸᒎᮃ࡞࡝ࢆୡ⏺ࡢືࡀᐇ⏝࡟౪ࡉࢀ࡚࠸ࡿࠋNb3Sn ⥺ᮦࡢ〇ἲࡣᵝࠎྥ࡜᭱᪂ࢺࣆࢵࢡࢫࢆ஺࠼࡞ࡀࡽࢃ࠿ࡾࡸࡍࡃ

࠶ࡿࡀࠊࡑࢀࡒࢀ㛗ᡤ࡜▷ᡤࡀ࠶ࡾࠊ⌧ᅾࡶ▷ᡤゎㄝࡍࡿࠋࢆ⿵࠺ࡼ࠺࡞◊✲㛤Ⓨࡀ⾜ࢃࢀ࡚࠸ࡿࠋࡑࡢ௚ࡢ
A15 ᆺ໬ྜ≀ࠊ⪏ࡦࡎࡳ≉ᛶ࡟ඃࢀࡿ Nb3Al ࡢ⥺

2. ྜ㔠⣔⥺ᮦ㸦Nb-Ti㸧

ᮦ㛤Ⓨࡀᆅ㐨࡟㐍ࡵࡽࢀ࡚࠸ࡿࠋ1980 ᖺ௦ᚋ༙༢యඖ⣲ࡢ㉸ఏᑟయ࡛ࡣࠊ㔠ᒓⓗᛶ㉁ࢆ♧ࡍࡀ࠿ࡽୡ⏺ⓗ࡞ࣇ࢕࣮ࣂ࣮ࡀᕳࡁ㉳ࡇࡾࠊ⥆ࠎ࡜⮫☢ሙ࡟ᙅ࠸➨㸯✀㉸ఏᑟయ࡛࠶ࡿࡇ࡜ከ࠸ࠋྜ㔠⏺

ᗘ㸦Tc㸧ࡀ᭦᪂ࡉࢀ࡚ࡁࡓ㖡㓟໬≀⣔㉸ఏᑟ໬ࡍࡿࡇ࡜࡛➨㸰✀㉸ఏᑟయ࡜࡞ࡾ⮫⏺☢ሙࡀయࡢ⥺ᮦ㛤Ⓨࡣࠊ⌧ᅾࡣᴫࡡ Bi ⣔࡜ᕼᅵ㢮⣔ࡢቑຍࡍࡿࡓࡵࠊᙉ࠸☢ሙⓎ⏕ࢆᛕ㢌࡟ࡋࡓ㟁☢▼㸰✀㢮࡟㞟⣙ࡉࢀ࡚࠸ࡿࠋᅜᐙࣉࣟࢪ࢙ࢡࢺ➼࡟⏝⥺ᮦ࡜ࡋ࡚ᒎᘏᛶ࡟ඃࢀࡓྜ㔠⣔㉸ఏᑟయࡀࡼࡾ୍㒊ࡢ⥺ᮦࡀᛂ⏝ᶵჾ࡟㐺⏝ࡉࢀ࡚࠸ࡿࡀࠊ

◊✲㛤Ⓨࡢᑐ㇟࡜࡞ࡗࡓࠋ࿘ᮇᚊ⾲ࡢ IV ᪘࡜ V኱ࡁࡃᕷሙࡀᣅࡅࡿ࡟ࡣ⮳ࡗ࡚࠸࡞࠸ࠋ2001 ᖺ᪘ࡢ⤌ࡳྜࢃࡏ࡛㧗࠸ Tc ࡜ Bc2 ࡀᚓࡽࢀࡿሙྜ

࡟ᡃࡀᅜ࡛ぢฟࡉࢀࡓ MgB2 ㉸ఏᑟయࡣࠊࢩࣥࣉ

ࡀከࡃࠊ1961 ᖺ㡭࡟ࡑࢀࡽྜ㔠⣔㉸ఏᑟ࡟㛵ࡍࣝ࡞໬Ꮫ⤌ᡂ࠿ࡽ᪩ᮇࡢᐇ⏝໬ࡀᮇᚅࡉࢀ࡚ࡁࡿㄽᩥࡀⓎ⾲ࡉࢀ࡚࠸ࡿࠋᡃࡀᅜ࡟࠾࠸࡚ࡣࠊ

ࡓࠋ᪤࡟⡿ᅜࡸ㡑ᅜࠊ࢖ࢱࣜ࢔࡞࡝࠿ࡽ⥺ᮦࡀᕷ

1962 ᖺ࡟ᪧ⛉Ꮫᢏ⾡ᗇ㔠ᒓᮦᩱᢏ⾡◊✲ᡤ㸦⌧㈍ࡉࢀࠊ࣮࢜ࣉࣥᆺ MRI ࡸ㟁ຊ౪⤥ࢣ࣮ࣈࣝࡢ≀㉁࣭ᮦᩱ◊✲ᶵᵓ㸦NIMS㸧㸧ࡢኴยᕝᜤ἞ࡀ Nb-ࢹࣔࣥࢫࢺ࣮ࣞࢩࣙࣥࡶ⾜ࢃࢀ࡚࠸ࡿࠋ᭱㏆ࡣࠊ

Zr ⥺ᮦࡢ◊✲࡟╔ᡭࡋࡓ࡜ሗ࿌ࡉࢀ࡚࠸ࡿ[1]ࠋ⌧ᾮయỈ⣲ࡢ෭⇕ࢆ฼⏝ࡋࡓ஺ὶ⏝ᛂ⏝ᶵჾ࡬ࡢ

ᅾ࡛ࡣࠊNb-Zr ࡼࡾࡶ Bc2 ࡀ㧗ࡃୟࡘຍᕤᛶ࡟ඃ

ᒎ㛤ࡶᮇᚅࡀ㧗ࡲࡗ࡚࠸ࡿࠋ2008 ᖺ࡟ྠࡌࡃᡃ

ࢀࡿ Nb-Ti ⥺ᮦࡀᐇ⏝⥺ᮦࡢ୺ᙺ࡜࡞ࡗ࡚࠸ࡿࠋࡀᅜ࡛Ⓨぢࡉࢀࡓ㕲⣔㉸ఏᑟయࡣࠊ☢ᛶࢆ♧ࡍඖ⣲ࢆྵࢇࡔ㉸ఏᑟࡀẚ㍑ⓗ㧗࠸ Tc ࢆ♧ࡍࡓࡵࠊᇶ♏≀ᛶࡸ⌮ㄽ≀⌮ศ㔝࠿ࡽᙉ࠸⯆࿡ࢆ㞟ࡵࡓࠋከࡃࡢ㛵㐃≀㉁ࡀぢฟࡉࢀ࡚࠸ࡿࡀࠊከࡃࡣ㕲࡜࡜ࡶ࡟ẘᛶࡢ࠶ࡿࣄ⣲ࢆྵࡴࡓࡵࠊୡ⏺ⓗ࡟ぢࡿ࡜⥺ᮦ㛤Ⓨࡣᾘᴟⓗ࡛࠶ࡿࠋࡋ࠿ࡋࠊཎᩱࡀẚ㍑ⓗᏳ౯࡛࠶ࡿࡇ࡜ࠊప ࡛ࡢୖ㒊⮫⏺☢ሙ㸦Bc2㸧
ࡀ㧗࠸ࡇ࡜ࠊ㔠ᒓ⣔࡜ྠࡌࡃ s Ἴ㉸ఏᑟ࡛࠶ࡿࡓ
ࡵ㖡㓟໬≀⣔࡯࡝⤖ᬗ㓄ྥ࡟ᩄឤ࡛࡞࠸ࡇ࡜࡞
࡝ࡢ฼Ⅼ࡟ࡼࡾࠊ୰ᅜ࡛ẚ㍑ⓗάⓎ࡟⥺ᮦ㛤Ⓨࡀ㐍ࡵࡽࢀ࡚࠸ࡿࠋ
ࡇࡢࡼ࠺࡟ࠊ⌧ᅾࡢ㉸ఏᑟ⥺ᮦࡢ◊✲㛤Ⓨࡣࠊձྜ㔠⣔ࠊղA15 ᆺ໬ྜ≀⣔ࠊճ㖡㓟໬≀⣔ࠊմ

㸲㸫 1

ᅗ 1. Nb-Ti ᖹ⾮≧ែᅗࠋᅗ 2. Nb-Ti ⤌ᡂ࡜ Tc ཬࡧ Bc2 ࡢ㛵ಀࠋ

ᅗ 3. Nb-Ti㸦ǃ ┦㸧୰࡟ᯒฟࡋࡓ ǂ-Ti[4]ࠋᅗ 1 ࡣ Nb-Ti ᖹ⾮≧ែᅗ࡛࠶ࡿࠋ඲⋡ᅛ⁐⣔࡛࠶ຠ࡟ാࡃࡀࠊ
J. B. Vetrano ࡜ R. W. Boom ࡣ 400ΥࡿࡀࠊNb ഃ࡛ࡣయᚰ❧᪉᱁Ꮚ㸦bcc㸧ࡢ ǃ ┦࡛ࠊ⛬ᗘࡢ᫬ຠ⇕ฎ⌮࡛ᅗ 3 ࡟♧ࡍࡼ࠺࡞ᚤ⣽࡞ ǂ-Ti

Ti ഃ࡟࡞ࡿ࡜ᐊ ࡛ࡣභ᪉᭱ᐦ᱁Ꮚ㸦hcp㸧ࡢ ǂ⢏Ꮚࢆᯒฟࡉࡏࡿᡭἲࢆぢฟࡋࠊ㧗☢ሙୗ࡛ࡢ⮫┦ࡀᯒฟࡍࡿࠋbcc ࡣ hcp ࡟ẚ࡭࡚ࡍ࡭ࡾ⣔ࡀከ⏺㟁ὶᐦᗘ㸦Jc㸧ࡢྥୖ࡟ᡂຌࡋࡓ[3]ࠋᅗ 3 ࡣ㏱ࡃຍᕤᛶ࡟ඃࢀ࡚࠸ࡿࠋᅗ 2 ࡣࠊNb-Ti ⤌ᡂ࡜ Tc㐣㟁Ꮚ㢧ᚤ㙾࡛᧜ᙳࡋࡓ Nb-Ti ⥺ᮦࡢ᩿㠃෗┿࡛ཬࡧ Bc2 ࡢ㛵ಀ࡛࠶ࡿࠋ⣙ 22wt%Ti ⤌ᡂ࡛᭱㧗

࠶ࡿ[4]ࠋⓑ࠸ࣜ࣎ࣥ≧ࡢ⤌⧊ࡀ ǂ-Ti ࡛࠶ࡿࠋ್࡜࡞ࡿ 10.1K ࡢ Tc ࢆ♧ࡍࡀࠊ
Bc2 ࡣ⣙ 47wt%Ti

ලయⓗ࡞⥺ᮦ〇㐀ࡣ௨ୗࡢᕤ⛬࡛⾜ࢃࢀࡿࠋࡲ

⤌ᡂ࡛᭱ࡶ㧗ࡃ࡞ࡾࠊTc ࡶ 9.0K ⛬ᗘࢆ⥔ᣢࡋ࡚ࡎࠊ࢔࣮ࢡ⁐ゎ࠶ࡿ࠸ࡣ㟁Ꮚࣅ࣮࣒⁐ゎ࡛ᡤᮃࡢ࠸ࡿࡓࡵ࡟ࠊᐇ⏝⥺ᮦ࡟ࡣ 45-50wt%Ti ⤌ᡂࢆ⏝⤌ᡂࡢ Nb-Ti ࢖ࣥࢦࢵࢺࡀ⁐〇ࡉࢀࡿࠋ኱ࡁ࠸ࡶ

࠸ࡿሙྜࡀከ࠸ࠋࡲࡓ㉸ఏᑟ⥺ᮦ࡟ࡣࠊᴟప ࡛ࡢ࡛ࡣ┤ᚄ 300mm ⛬ᗘ࡟࡞ࡿࠋࡇࡢ࢖ࣥࢦࢵࢺ

ࡢࡺࡽࡂࢆཷࡅࡓᖖఏᑟࡢఏ᧛ࢆ㜵ࡄࡓࡵࠊ㟁Ẽ

ࢆᆒ㉁໬⇕ฎ⌮ࠊ㘫㐀ࠊᐜయ໬⇕ฎ⌮ࢆᐇ᪋ࡋࠊ

᢬ᢠࡀᑠࡉ࠸㧗⣧ᗘࡢ㖡ࡀ」ྜࡉࢀ࡚࠸ࡿࠋ1965

ᆒ㉁࡞ Nb-Ti ྜ㔠ࣟࢵࢻࢆస〇ࡍࡿࠋࡇࡢࣟࢵࢻ

ᖺ࡟ Z. J. J. Stekley ࡽ࡟ࡼࡾᥦၐࡉࢀࡓ㖡࡟ࡼࢆᏳᐃ໬ᮦ࡜࡞ࡿ↓㓟⣲㖡⟶㸦஺ὶ⏝⥺ᮦ࡛ࡣ࢟ࡿᏳᐃ໬࡛࠶ࡿ[2]ࠋ⣧㖡ࡣᖖఏᑟࡀ㉸ఏᑟ࡟ᅇ᚟

ࣗࣉࣟࢽࢵࢣࣝ⟶ࢆ౑࠺ሙྜࡶ࠶ࡿ㸧࡟ᤄධࡋ࡚

ࡍࡿ㛫ࡢ㎽ᅇ㊰࡜࡞ࡿࠋࡲࡓࠊ㉸ఏᑟ㒊ࢆ୍ࡘࡢࣇࢱࢆࡋ࡚㟁Ꮚࣅ࣮࣒⁐᥋ࡋࠊ㟼Ỉᅽࣉࣞࢫ࡛㝽኱ࡁ࡞ሢ࡜ࡏࡎᑠࡉࡃศ๭ࡍࡿ࡜ࠊ඲యࡣྠࡌయ

㛫ࢆ࡞ࡃࡋࡓᚋ࡟ࠊ⇕㛫ᢲฟຍᕤࢆ⾜࠺ࠋࡑࡢᚋ

✚࡛ࡶ☢ሙࡀኚືࡋࡓሙྜࡢ☢᮰ࡢ౵ධࡀ⦆ࡸ

࡟኱ᆺࢻ࣮ࣟ࣋ࣥࢳࡸఙ⥺ᶵ࡛෭㛫ᘬᢤຍᕤࢆ

࠿࡟࡞ࡿࡓࡵ㉸ఏᑟ≧ែࡀᏳᐃ໬ࡍࡿࠋᚑࡗ࡚ࠊ

ᐇ᪋ࡋ࡚ࠊභゅᙧࡢ」ྜ⥺ࢆస〇ࡍࡿࠋࡇࡢ」ྜ

ᐇ⏝㉸ఏᑟ⥺ᮦࡢෆ㒊ࡣࠊࡓࡃࡉࢇࡢ⣽࠸㉸ఏᑟ⥺ࢆఱᮏࡶ᮰ࡡ࡚෌ࡧ↓㓟⣲㖡⟶࡟ᤄධࡋࠊ㟁Ꮚࣇ࢕࣓ࣛࣥࢺ࠿ࡽ࡞ࡿከⰺᵓ㐀࡜࡞ࡗ࡚࠸ࡿࠋࡉ

ࣅ࣮࣒⁐᥋ࠊ⇕㛫ᢲฟࠊ෭㛫ᘬᢤຍᕤࡀ⾜ࢃࢀࡿࠋࡽ࡟ࠊከⰺᵓ㐀࡜ࡋ࡚ࡶᖖఏᑟࡢ⥺ᮦẕᮦࢆ௓ࡋ௙ᵝ࡟ᛂࡌ࡚ࡇࡢᕤ⛬ࢆᩘᅇ⧞ࡾ㏉ࡋ࡚ࠊᡤᐃࡢ

࡚㐽ⶸ㟁ὶࡀㄏ㉳ࡉࢀࠊࡇࢀࡀ㉸ఏᑟࡢᏳᐃ໬ࢆ

ᮏᩘ࡜እᚄࡢ Nb-Ti ࣇ࢕࣓ࣛࣥࢺࡀ」ྜࡉࢀࡓᴟ

㜼ᐖࡍࡿࠋ㟁ὶࡢ࣮ࣝࣉࢆᑠࡉࡃࡍࡿࡓࡵ࡟ࠊ⥺⣽ከⰺ⥺ᮦࡀస〇ࡉࢀࡿࠋึᮇࡢ Nb-Ti ࢖ࣥࢦࢵᮦࡣྑᅇࡾ㸦s ᪉ྥ㸧࠶ࡿ࠸ࡣᕥᅇࡾ㸦z ᪉ྥ㸧࡟ࢺ࠿ࡽ᭱⤊ⓗ࡞ᴟ⣽ከⰺ⥺ᮦ࡟⮳ࡿࡲ࡛ࠊNb-Ti

ࢶ࢖ࢫࢺࡉࢀࡓ㸦ࡡࡌࡽࢀࡓ㸧ᵓ㐀࡜࡞ࡗ࡚࠸ࡿࠋ

ྜ㔠ࡣ᩿㠃ῶᑡ⋡࡜ࡋ࡚ 108㹼1010 ࡟ࡲ࡛࠾ࡼࡪ

ࡉࡽ࡟ࠊ㧗☢ሙୗ࡛኱㟁ὶࢆ㏻㟁ࡍࡿ࡟ࡣ☢᮰ࢆᙉຍᕤࡀຍࢃࡿࠋࡇࡢࡼ࠺࡞ᙉຍᕤ࡟⪏࠼ࡿඃࢀࣆࣥṆࡵࡍࡿࣆࣥࢽࣥࢢࢭࣥࢱ࣮ࡀᚲせ࡜࡞ࡿࠋࡓረᛶຍᕤᛶࡀ Nb-Ti ࡟ࡣഛࢃࡗ࡚࠸ࡿࠋࡉࡽ࡟

ࣆࣥࢽࣥࢢࢭࣥࢱ࣮ࡣࢥࣄ࣮ࣞࣥࢫ㛗⛬ᗘࡢ኱ఙ⥺ຍᕤ㏵୰࡛ࡣࠊ๓㏙ࡋࡓ ǂ-Ti ࢆᯒฟࡉࡏࡿࡓ

ࡁࡉ㸦Nb-Ti ࡛࠶ࢀࡤ 5nm ⛬ᗘ㸧ࡢᖖఏᑟ㒊ࡀ᭷ࡵࡢ᫬ຠ⇕ฎ⌮ࡀ᪋ࡉࢀࡿࠋǂ-Ti ࡢࢧ࢖ࢬࡸ⢏Ꮚ

㸲㸫 2

ᅗ 5ǃ㸫W ᆺ㸦A15 ᆺ㸧⤖ᬗᵓ㐀ࠋA3B ⤌ᡂ࡛㯮Ⰽࡀ A ཎᏊࠊ ⅊Ⰽࡀ B ཎᏊࠋᅗ 4. ⣧ Nb ࡢேᕤࣆࣥ㸦ⓑⰍᒙ㸧ࡀᒙ≧࡟ᑟධ
ࡉࢀࡓ Nb-Ti ࣇ࢕࣓ࣛࣥࢺ[6]ࠋ
㛫㝸ࠊᙧ≧࡞࡝ࡣᙉࡃ☢᮰ࡢࣆࣥṆࡵ࡟ᙳ㡪ࡋࠊࡑࡢ≧ែࡣຍᕤ᮲௳࡟ࡼࡾኚ໬ࡍࡿࠋᚑࡗ࡚ࠊᛂ
⏝ࡍࡿ☢ሙ㡿ᇦ࡛㧗࠸ Jc ࢆᚓࡿࡓࡵ࡟ࠊຍᕤ᮲
௳ࢆ᭱㐺໬ࡍࡿᚲせࡀ࠶ࡾࠊヲ⣽ࡣ⥺ᮦ࣓࣮࣮࢝
ྛ♫ࡢࣀ࢘ࣁ࢘࡜ࡋ࡚㠀බ㛤࡜ࡉࢀ࡚࠸ࡿࠋࡑࡢ
௚ࠊ஺ὶ⏝ከⰺ⥺ᮦ࡛ࡣ Nb-Ti ࣇ࢕࣓ࣛࣥࢺࡀࢧ
ࣈ࣑ࢡࣟࣥᚄࡲ࡛⣽ࡃ࡞ࡿࡓࡵࠊǂ-Ti ⢏Ꮚࢆᯒฟࡉࡏࡿ᫬ຠ⇕ฎ⌮ࢆ⾜࠺࡜ࠊNb-Ti ࣇ࢕࣓ࣛࣥࢺ
࡜ẕᮦࡢ㖡࡜ࡢ㛫ࡢ⏺㠃཯ᛂ࡛⬤࠸ CuTi ໬ྜ≀ࡀ⏕ᡂࡋ࡚⥺ᮦຍᕤ࡟ᨭ㞀ࢆ୚࠼ࡿࠋᚑࡗ࡚ࠊ᫬
ຠ⇕ฎ⌮ࢆ⾜࠺ࡇ࡜ࡀ࡛ࡁ࡞࠸ࡓࡵ࡟⣧ Nb ➼ࢆࢼࣀࢫࢣ࣮࡛ࣝ」ྜຍᕤࡍࡿேᕤࣆࣥᑟධࡢ◊✲㛤Ⓨࡀ⾜ࢃࢀࡓ[5, 6]ࠋ

3. A15 ᆺ໬ྜ≀⣔⥺ᮦ
3.1. Nb3Sn ⥺ᮦ

A15 ᆺ㔠ᒓ㛫໬ྜ≀࡟ὀ┠ࡋࡓ⡿ᅜ࣋ࣝ◊✲ᡤࡢ Matthias ࡽࡀ Nb3Sn ࢆぢฟࡋࠊTc ࡀ 18.05K࡜ሗ࿌ࡋࡓ[9]ࠋࡉࡽ࡟ 4 ᖺᚋࡢ 1958 ᖺࠊྠࡌࡃ
Matthias ࡢࢢ࣮ࣝࣉࡀᘬࡁ⥆ࡁ Nb3Al ࢆぢฟࡋࠊ
17.5K ࡢ Tc ࡜ሗ࿌ࡋࡓ[10]ࠋ ወࡋࡃࡶ Nb3Sn ࡜
Nb3Al ࡣྠࡌ◊✲ࢢ࣮ࣝࣉ࡟ࡼࡾぢฟࡉࢀࡓ㉸ఏᑟయ࡛ࠊ⤖ᬗᵓ㐀ࡶྠࡌ A15 ᆺ࡟ศ㢮ࡉࢀࡿ඗ᘵ
࡜ゝ࠼ࡿࠋNb3Sn ࡢ⥺ᮦ໬ཬࡧࡑࡢ㧗☢ሙ≉ᛶࡢ᭱ึࡢ᳨ウࡣࠊⓎぢ⪅ࡢ Matthias ࡢ່ࡵ࡛ྠ൉
ࡢ Kunzler ࡽ࡟ࡼࡾ⾜ࢃࢀࡓ[11]ࠋ㔠ᒓ㛫໬ྜ≀࡛࠶ࡿ Nb3Sn ࡣᶵᲔⓗ࡟⬤ࡃࠊ⥺ᮦ໬ࡣᐜ࡛᫆࡞
࠸ࡇ࡜ࡣ Kunzler ࡶㄽᩥࡢ୰࡛ࡶ㏙࡭࡚࠸ࡿࠋࡑ
ࡇ࡛ࠊᘏᛶࡢ࠶ࡿ㔠ᒓ⟶࡟ Nb3Sn ⢊ᮎࢆ඘ሸࡋ
࡚ఙ⥺ຍᕤࡍࡿࠊ࠸ࢃࡺࡿ PIT㸦Power-In-Tube㸧ἲ࡟ࡼࡿ⥺ᮦ໬ࡀヨࡳࡽࢀࡓࠋPIT ἲࡣྠࡌࡃ⬤࠸㓟໬≀㧗 ㉸ఏᑟయࡸ஧࣍࢘໬࣐ࢢࢿࢩ࣒࢘
ࡢ⥺ᮦ໬ࣉࣟࢭࢫ࡜ࡋ࡚⌧ᅾࡶ⏝࠸ࡽࢀ࡚࠸ࡿࠋ
ࡑࡢᚋࠊ1965㹼1970 ᖺ㡭ࡣᅗ 6 ࡟♧ࡍࡼ࠺࡞⣧ࢽ࢜ࣈࡢୗᆅࢸ㸫ࣉࡢ⾲㠃࡟⁐⼥ Sn ࢆ㐃⥆ⓗ࡟1953 ᖺࠊ⡿ᅜࢩ࢝ࢦ኱Ꮫࡢ Hardy ࡜ Hulm ࡣࠊ✀ࠎࡢ໬ྜ≀㸦࣍࢘໬≀ࠊ❅໬≀ࠊ㓟໬≀ࠊࢣ࢖໬≀ࠊࢤ࣐ࣝࢽ࣒࢘໬ྜ≀࡞࡝㸧ࡀ㉸ఏᑟయ࡛࠶
ࡿࡇ࡜ࢆሗ࿌ࡋࡓ[7]ࠋᙜ᫬࡟ሗ࿌ࡉࢀࡓᵝࠎ࡞㉸ఏᑟ໬ྜ≀ࡢෆࠊᅗ 5 ࡟♧ࡍ⤖ᬗᵓ㐀ࡢ ǃ㸫ࢱࣥࢢࢫࢸࣥᆺ໬ྜ≀ࡢ V3Si ࡛ 17.1K ࡜᭱ࡶ㧗࠸ Tc
ࡀᚓࡽࢀࡿࡇ࡜ࢆぢฟࡋࡓࠋྠ⤖ᬗࡣఏ⤫ⓗ࡞⤖ᬗᵓ㐀ศ㢮ἲ㸦Strukturbericht Designation㸧࡛ࡣ A15 ᆺ࡜ࡼࡤࢀࠊA3B ࡢ⤌ᡂẚ࡛ A ཎᏊࡣ஫࠸࡟ᆶ┤࡞㙐≧ࡢ㓄ิࢆ⤌ࢇ࡛࠸ࡿࠋࡑࡢᚋࡢ◊✲࡛ A ཎᏊࡢ㙐≧ࡢ㓄ิࡀ㧗࠸ Tc ࡀᚓࡽࢀࡿᅉ
Ꮚ࡛࠶ࡿ࡜⪃࠼ࡽࢀ࡚࠸ࡿ[8]ࠋ⩣ᖺࡢ 1954 ᖺࠊ

㸲㸫 3

ᅗ 6. ⣧ Nb ࢸ࣮ࣉ࡟⁐⼥ Sn ࡀ࣓ࢵ࢟ࡉࢀࡓ
Nb3Sn ࢸ࣮ࣉ[12]ࠋ

⿕そࡍࡿᣑᩓࢸ㸫ࣉ[12]ࡸࠊࣁࢫࢸࣟ࢖࡞࡝ࡢ⪏⇕ྜ㔠ࢸ࣮ࣉࡢ⾲㠃࡟Ẽ┦㑏ඖἲ࡛ Nb3Sn ࢆᯒฟᡂ⭷ࡍࡿࢸ࣮ࣉᑟయ[13]ࡢ㛤Ⓨࡀ㐍ࡵࡽࢀࠊ15T ⣭㉸ఏᑟ࣐ࢢࢿࢵࢺࡀ㛤ⓎࡉࢀࡓࠋNb3Sn ࢸ࣮ࣉᑟయࡣࠊ⤖ᬗ㓄ྥไᚚࡣ୙せ࡞ࡶࡢࠊ⌧ᅾࡢḟୡ௦㧗 ㉸ఏᑟ⥺ᮦ࡜ࡋ࡚ᮇᚅࡉࢀ࡚࠸ࡿᕼᅵ㢮⣔ࢥ࣮ࢸࢵࢻࢥࣥࢲࢡࢱ࣮࡜㢮ఝࡢᵓ㐀࡛࠶ࡿࠋࡇࡢ Nb3Sn ࢸ࣮ࣉᑟయࡣࠊNb3Sn ࡢ༢┦ࢆᚓࡿࡓ ࡵ ࡟ 1000 Υ ⛬ ᗘ ࡢ 㧗 ⇕ ฎ ⌮ ࡀ ⾜ ࢃ ࢀ ࠊ
Kunzler ࡽࡢ PIT ⥺ᮦࡶྠᵝ࡛࠶ࡗࡓࠋ㧗 ⇕ฎ⌮࡛ࡣ Nb3Sn ࡢ⢏ᡂ㛗ࡀⴭࡋࡃࠊ☢᮰ࡢࣆࣥṆࡵ࡟᭷ຠ࡞⤖ᬗ⢏⏺ᐦᗘࡀᑡ࡞ࡃ࡞ࡿࠋࡇࡢࡓ
ࡵࠊ࡝ࡕࡽࡢ⥺ᮦࡶ໬ྜ≀࠶ࡓࡾࡢ⮫⏺㟁ὶᐦᗘ㸦Jc㸧ࡣ㧗ࡃ࡞࠸ࠋࡲࡓࠊᴟ⣽ከⰺ⥺ᵓ㐀࡛ࡣ࡞࠸ࡓࡵ࡟஺ὶᦆኻࡀ኱ࡁࡃࠊ࣐ࢢࢿࢵࢺࡢ☢ሙࡢᤲᘬ㏿ᗘࡣ㠀ᖖ࡟ࡺࡗࡃࡾࡔࡗࡓࠋຍ࠼࡚ࢸ࣮ࣉᑟ
య࡛ࡣㄏ㉳ࡉࢀࡿ㐽ⶸ㟁ὶࡢᙳ㡪࡛ᐃ᱁☢ሙࡢ
Ⓨ⏕࡟ࡶၥ㢟ࡀ࠶ࡗࡓࠋࡇࡢⅬࡣ⌧ᅾࡢࢥ࣮ࢸࢵ
ࢻࢥࣥࢲࢡࢱ࣮ࡢ㔜せㄢ㢟࡜࡞ࡗ࡚࠾ࡾࠊ࣮ࣞࢨ
࣮࡛ᖜ⣽ࡃษࡾ㎸ࡳࢆධࢀࡿࢫࢡࣛ࢖ࣅࣥࢢຍ
ᕤ➼ࡢ᳨ウࡀ㐍ࡵࡽࢀ࡚࠸ࡿ[14]ࠋNb3Sn ࡟࠾࠸࡚ࡣࠊᚋ࡟ࣈࣟࣥࢬἲࡀⓎ⾲ࡉࢀ࡚㏿࠸☢⏺ኚ໬࡟ᑐࡋ࡚ࡶᏳᐃ࡞ᴟ⣽ከⰺᵓ㐀ࡢ⥺ᮦ〇㐀ࡀྍ⬟࡜࡞ࡾࠊNb3Sn ࢸ࣮ࣉᑟయࡢ㛤Ⓨࡣᖥࢆ㛢ࡌࡓࠋࣈࣟࣥࢬἲࡣࠊᡃࡀᅜ࡟࠾ࡅࡿ㉸ఏᑟ⥺ᮦ㛤Ⓨࡢඛ㥑ࡅ࡛࠶ࡿኴยᕝᜤ἞ࡽ࡟ࡼࡿ 1960 ᖺ௦ᚋ༙ࡢ V3Ga ࡢ◊✲[15]ࡀ※ὶ࡜࡞ࡿࠋኴยᕝࡽࡣࠊ
V ࢸ࣮ࣉࡢ⾲㠃࡟ Ga ࢆ⿕そࡋ࡚୧⪅ࡢ㛫ࡢᣑᩓ཯ᛂࢆ◊✲ࡋ࡚࠸ࡓࠋV3Ga ࡶ Nb3Sn ࡜ྠࡌࡃA15 ᆺ໬ྜ≀࡟ศ㢮ࡉࢀࠊࡑࡢ༢┦ࢆᚓࡿ࡟ࡣ㧗⇕ฎ⌮ࡀᚲせ࡛࠶ࡿࠋ࡜ࡇࢁࡀࠊ⿕そࡋࡓ Ga
ࡢ⾲㠃࡟ Cu ࢆ࣓ࢵ࢟ࡋ࡚࠿ࡽ⇕ฎ⌮ࡍࡿ࡜ࠊ650
㹼750Υ⛬ᗘࡢẚ㍑ⓗప ⇕ฎ⌮࡛ V3Ga ᣑᩓᒙࡀཌࡃ⏕ᡂࡉࢀࡿࡇ࡜ࡀኴยᕝࡽ࡟ࡼࡾぢฟࡉࢀࡓ[14]ࠋࡇࡢ Cu ࡟ࡼࡿᣑᩓ཯ᛂࡢಁ㐍ࡣ Nb3Sn
࡛ࡶྠᵝ࡟ࡑࡢຠᯝࡀ☜ㄆࡉࢀࡓࠋࡑࡢᚋࠊᒎᘏ
ᛶࡢ࠶ࡿࣈࣟࣥࢬ㸦Cu-Sn㸧ྜ㔠࡜ Nb ࢆ」ྜຍᕤࡋ࡚ࡑࡢ⏺㠃࡟ Nb3Sn ┦ࢆ⏕ᡂࡉࡏࡿᡭἲ࡟
ኚ㑄ࡋ࡚࠸ࡗࡓࡇ࡜࠿ࡽࠊᚋ࡟ࠕࣈࣟࣥࢬἲࠖ࡜
࿧ࡤࢀࡿࡼ࠺࡟࡞ࡗࡓࠋᅗ 7 ࡣࡑࡢ཯ᛂཎ⌮ࡢ࢖ࣛࢫࢺ࡛࠶ࡿࠋ⡿ᅜࣈࣝࢵࢡ࣊ࣈࣥᅜ❧◊✲ᡤࡢᮎỌṇᶞࡽࡀࠊࣈࣟࣥࢬẕᮦ࡟㸵ᮏࡢ Nb ⰺࢆᤄධࡋࡓከⰺᵓ㐀ࡢ Nb3Sn ⥺ᮦࢆඛ㥑ࡅ࡚ሗ࿌ࡋ
ࡓࡢࡣ 1972 ᖺࡢࡇ࡜࡛࠶ࡿ[16]ࠋࡇࡢ」ྜຍᕤἲࢆ⏝࠸࡚ࠊࡉࡽ࡟ⰺᩘࡀከࡃୟࡘⰺᚄࡀ⣽࠸ᴟ⣽ከⰺ⥺ᮦࡢ㛤Ⓨࡀୡ⏺ⓗ࡟ྲྀࡾ⤌ࡲࢀ࡚ Nb3Sn⥺ᮦࡢᐇ⏝໬ࡀ୍Ẽ࡟㐍ࢇࡔࠋ෭㛫࡛ᘏᛶࡢ࠶ࡿ
ࣈࣟࣥࢬྜ㔠ࡣ㠃ᚰ❧᪉ᬗ㸦fcc㸧ࡢ ǂ ┦࡛ࠊCu୰࡟ᅛ⁐ࡉࢀࡿ Sn ⃰ᗘࡀቑ࠼ࢀࡤ Nb ࡜ᣑᩓ཯ᛂᚋ࡟⏕ᡂࡉࢀࡿ Nb3Sn ࡀቑຍࡋ࡚⮫⏺㟁ὶࡀྥୖࡍࡿࠋࡇࡢࡓࡵࠊཎᩱࣈࣟࣥࢬ୰ࡢ Sn ⃰ᗘࡢቑຍࡀ᳨ウࡉࢀࠊ14.0mass%ࠊ15.0mass%ࠊ
16.0mass%࡜ࣈࣟࣥࢬཎᩱࡢ Sn ⃰ᗘࡀ㧗ࡵࡽࢀࠊࡑࢀࡽࢆ౑ࡗࡓ Nb3Sn ⥺ᮦࡀ㛤Ⓨࡉࢀ࡚ࡁࡓࠋNIMS ࡟࠾ࡅࡿ㧗☢ሙ NMR 㛤Ⓨ࡛ࡣࠊࡑࡢ
᭱ෆᤄࢥ࢖ࣝ࡟ 16mass%ࡢ㧗 Sn ⃰ᗘࣈࣟࣥࢬ
ࢆẕᮦ࡜ࡋࡓ Nb3Sn ከⰺ⥺ᮦࡀ౑⏝ࡉࢀࡓ㸦ᅗ
8㸧[17]ࠋࡉࡽ࡟௖ᅜࡢ࢝ࢲࣛࢵࢩ࡛ࣗᘓタ୰ࡢᅜ㝿⇕᰾⼥ྜᐇ㦂⅔㸦ITER㸧ࡸ 2020 ᖺ࡟⿦⨨⤌❧ࡀ᏶஢ࡋࡓ㔞Ꮚ⛉Ꮫᢏ⾡◊✲㛤Ⓨᶵᵓ㸦QST㸧ࡢᅗ 8. 㧗 Sn ⃰ᗘ㸦16mass%㸧ࣈࣟࣥࢬࢆẕᮦ
࡜ࡋࡓ Nb3Sn ᴟ⣽ከⰺ⥺㸦ᖹゅ⥺㸧ࠋእ࿘㒊ࡣᏳᐃ໬ࡢࡓࡵࡢ↓㓟⣲㖡ࠋNb ⰺࡣ
35,910 ᮏࠋ୰ኸ㒊ࡣ⿵ᙉࡢࡓࡵࡢ Ta[17]ࠋ

ᅗ 7. Nb3Sn ࡢప ⇕ฎ⌮࡟࠾ࡅࡿᣑᩓ⏕ᡂ࡟ᑐࡍࡿ㖡ࡢຠᯝࠋ

㸲㸫 4

JT-60SA ࡛ࡶྠᵝ࡞ 16mass%ࡢ Sn ⃰ᗘࡢࣈࣟࣥࢬἲ Nb3Sn ከⰺ⥺ᮦࡀ኱㔞࡟౪ࡉࢀࡓ[18]ࠋࡇ
ࡢࡼ࠺࡟ࠊࣈࣟࣥࢬἲ Nb3Sn ከⰺ⥺ᮦࡣ NbTi ྜ㔠⥺ᮦ࡛ࡣ⿵࠼࡞࠸㧗☢ሙ⏝ࡢ㉸ఏᑟ⥺ᮦ࡜ࡋ࡚኱ࡁ࡞ᡂຌࢆ཰ࡵࡓࠋࡓࡔࡋࠊࣈࣟࣥࢬྜ㔠୰ࡢ Sn ⃰ᗘࡀ 16mass%㸦ṇ☜࡟ࡣ 15.8mass%㸧
ࢆ㉸࠼ࡿ࡜ࠊᶵᲔⓗ࡟⬤ᙅ࡞ ǅ ┦㸦Cu41Sn11㸧ࡀᯒฟࡋ࡚ఙ⥺ຍᕤࡀ࡯ࡰ୙ྍ⬟࡜࡞ࡿ [19]ࠋᚑࡗ
࡚ࠊࣈࣟࣥࢬἲ Nb3Sn ⥺ᮦࡢ᭦࡞ࡿ≉ᛶྥୖࡣᮃࡵ࡞࠸࡜⪃࠼ࡽࢀࠊ㝈⏺࡜ࡢㄆ㆑ࡀᗈࡲࡾࡘࡘ
࠶ࡗࡓࠋࡋ࠿ࡋཎᩱࣈࣟࣥࢬࡢ࣓࣮࣮࡛࢝࠶ࡿ኱
㜰ྜ㔠ᕤᴗᡤ࡛ࡣࠊ16mass%ࢆࡣࡿ࠿࡟ୖᅇࡿ㉸㧗 Sn ⃰ᗘࣈࣟࣥࢬྜ㔠ࡢ㛤Ⓨࡀᆅ㐨࡟㐍ࡵࡽࢀࠋ᭱㏆ࠊ18.5mass%ࡶࡢ㉸㧗 Sn ⃰ᗘࣈࣟࣥࢬ
ࢆẕᮦ࡜ࡋࡓᴟ⣽ከⰺ⥺ࡢヨస࡟ᡂຌࡋࡓࡇ࡜
ࢆሗ࿌ࡋࡓ[20]ࠋᅗ 9 ࡣࡑࡢከⰺ⥺ࡢ᩿㠃෗┿࡛࠶
ࡿࠋNb ⰺࡢ࿘ᅖ࡟࠶ࡿࣈࣟࣥࢬẕᮦ࡟↓ᩘࡢᚤ⣽࡞ᯒฟ≀ࡀศᩓࡋ࡚࠸ࡿࠋࡇࡢᚤ⣽࡞ᯒฟ≀ࡣSn ࢆከࡃྵࢇࡔ CuSnTi ໬ྜ≀࡛ࠊࡇࢀࢆ㏣ຍࡢ Sn ౪⤥ඖ࡟฼⏝ࡋࡓ⤌⧊ไᚚࡀ⾜ࢃࢀ࡚࠸ࡿࠋ௒ᚋࠊࡉࡽ࡟࡝ࡇࡲ࡛ Sn ⃰ᗘࡢቑຍࡀ࡛ࡁ
࡚≉ᛶྥୖࡀᅗࡽࢀࡿ࠿ᮇᚅࡀ㧗ࡲࡿࠋࡲࡓࠊᑗ

ᅗ 9. ୡ⏺᭱㧗 Sn ⃰ᗘ㸦18.5mass%㸧ࡢࣈࣟࣥࢬྜ㔠ࢆẕᮦ࡜ࡋࡓ Nb3Sn ᴟ⣽ከⰺ⥺ࡢ᩿㠃෗┿ࠋୗᅗࡣࣇ࢕࣓ࣛࣥࢺ㒊ࡢᣑ኱෗┿ࠋࣈࣟࣥࢬẕᮦ࡟↓ᩘࡢ Sn ᇶᯒฟ⢏Ꮚࡀศᩓࠋ

᮶ࡢ᰾⼥ྜᐇド⅔࡬ࡢᛂ⏝ࢆ┠ᣦࡋ࡚ࠊࣈࣟࣥࢬ
ẕᮦ࡟ Zn ࡸ In ࢆከ㔞࡟ྵ᭷ࡉࡏ࡚ࠊ⇕ฎ⌮ᚋ࡟ពᅗⓗ࡟ࡑࢀࡽࡢඖ⣲ࢆẕᮦ࡟ṧ␃ࡉࡏ࡚⥺ᮦࡢ㧗ᙉᗘ໬ࢆᅗࢁ࠺࡜࠸࠺ࣘࢽ࣮ࢡ࡞ྲྀࡾ⤌ࡳࡶ⾜ࢃࢀ࡚࠸ࡿ[21]ࠋ㉸ఏᑟ࣐ࢢࢿࢵࢺࡢ㧗☢ሙ໬ࡸ኱ᆺ໬࡜࡜ࡶ࡟ࠊ㉸ఏᑟ⥺ᮦ࡟࠿࠿ࡿ㟁☢ຊ㸦ࣇ࣮ࣉຊ㸧ࡣ኱ࡁࡃ࡞ࡿࡓࡵ㧗ᙉᗘ໬ࡣ㔜せ࡞ㄢ㢟࡛࠶ࡿࠋࡇࢀࡲ࡛ࠊ⥺ᮦෆ㒊࡟㧗ᙉᗘ Ta ࢆ㓄⨨ࡋࡓࡾࠊ
Ᏻᐃ໬ࡢࡓࡵࡢ↓㓟⣲㖡ࢆ Cu-Nb ྜ㔠ࡸ࢔࣑ࣝࢼศᩓ㖡࡟⨨ࡁ᥮࠼ࡓࡾ࡞࡝ࡢᡭἲ
ࡀ࡜ࡽࢀ࡚ࡁࡓࡀࠊᙉᗘࡢቑຍࡢ௦ࢃࡾ࡟ Jc ࡸᏳᐃᛶࡀ୍㒊ࢺ࣮ࣞࢻ࢜ࣇ࡜࡞ࡗ࡚ࡁࡓࠋ⥺ᮦࡢ㧗ᙉᗘ໬࡜㉸ఏᑟ≉ᛶࡢ୧❧ࢆ┠ᶆ࡜ࡋ࡚࠾ࡾ
௒ᚋࡢᒎ㛤ࢆぢᏲࡾࡓ࠸ࠋ
୍᪉ࠊࣈࣟࣥࢬྜ㔠ࢆ⥺ᮦࡢฟⓎཎᩱ࡜ࡏࡎࠊ
Cu ࡜ Sn ࡜ Nb ࡢ 3 ✀㢮ࡢ㔠ᒓ࡟ศࡅ࡚ࡑࢀࡽ
ࢆ」ྜຍᕤࡍࡿ〇ἲࢆෆ㒊 Sn ᣑᩓἲ࡜࿧ࢇ࡛࠸
ࡿࠋẚ㍑ⓗᐜ᫆࡟⥺ᮦ඲య࡟࠾ࡅࡿ Sn ⃰ᗘࢆ㧗ࡵࡿࡇ࡜ࡀ࡛ࡁࡿࡀࠊࣈࣟࣥࢬἲ࡜ẚ㍑ࡋ࡚㉸ఏᑟࣇ࢕࣓ࣛࣥࢺᚄࢆᑠࡉࡃࡋ࡟ࡃ࠸ࡇ࡜ࡸ⥺ᮦࡢ㛗ᡭ᪉ྥࡢᆒ୍ᛶࡀࡸࡸຎࡿᣦ᦬ࡀ࠶ࡿࠋప⼥Ⅼࡢ⣧ Sn ࡀྵࡲࢀࡿࡓࡵ࡟ࠊࣈࣟࣥࢬἲ࡜␗࡞
ࡗ࡚୰㛫↝㕌ࡀ୙せ࡜࠸࠺≉ᚩࡀ࠶ࡿࠋࡇࢀࡣࠊ
⥺ᮦ〇㐀ࡢᕤᮇ▷⦰࡟ࡣ኱ࡁ࡞฼Ⅼ࡛࠶ࡿࡀࠊ୍
᪉࡛኱ᆺࣅࣞࢵࢺ࡟ࡼࡿ⇕㛫ᢲฟࡢ㐺⏝ࡀ㞴ࡋ࠸Ⅼࡣ㔞⏘ୖࡢ୙฼࡜࡞ࡿྍ⬟ᛶࡀ࠶ࡿࠋฟⓎ᫬ࡣ Cu ࡜ Sn ࡛ศ࠿ࢀ࡚࠸ࡿࡶࡢࡢࠊ⇕ฎ⌮ึᮇ࡟ࡲࡎࡣ Cu ࡜ Sn ࡀ཯ᛂࡋ࡚ࣈࣟࣥࢬࡀᙧᡂࡉ
ࢀࠊࡑࡢᚋ࡟ Nb ࡜཯ᛂࡋ࡚ Nb3Sn ࡀ⏕ᡂࡉࢀࡿࡓࡵࠊ཯ᛂ⤒㊰ࡣࣈࣟࣥࢬἲࡶෆ㒊 Sn ᣑᩓἲࡶྠࡌ࡜⪃࠼ࡽࢀࡿࠋణࡋࠊෆ㒊 Sn ᣑᩓἲ࡛ࡣ Snࡀ ኱ᖜ ࡟ከ࠸ ࡓࡵ ࡟ᆒ㉁ ࡞໬ Ꮫ㔞ㄽ ⤌ᡂ ẚࡢ
Nb3Sn ⤖ᬗࡸࠊᚤ⣽࡞➼㍈ᬗࡢ⤖ᬗ⢏ࡀᚓࡽࢀࡸ
ࡍࡃࠊ㧗☢ሙୗ࡛ࣈࣟࣥࢬἲࡼࡾ᱁ẁ࡟኱ࡁ࡞ Jc
ࡀᚓࡽࢀࡸࡍ࠸ࠋࡲࡓࠊ⣧ Nb ⟶ࡢෆഃ࡟ Sn ࣮࣋ࢫࡢ໬ྜ≀⢊ᮎࢆ඘ሸࡍࡿ〇ἲࡶᥦ᱌ࡉࢀ࡚
࠸ࡿࠋ඘ሸ⢊ᮎ࡟ࡣࠊNbSn2ࠊTa6Sn5ࠊCu5Sn4ࠊ
Ti2Sn3 ࡞࡝ࢆ౑⏝ࡍࡿᵝࠎ࡞ሗ࿌ࡀ࠶ࡿ[22]-[25]ࠋ
⢊ᮎࢆ౑⏝ࡍࡿࡓࡵ୍⯡ⓗ࡟ PIT ἲ࡜࿧ࡤࢀࡿ
ࡀࠊඛࡢ Kunzler ࡽࡢ PIT ⥺ᮦ࡜␗࡞ࡗ࡚ Nb ⟶࡜⢊ᮎࡢᣑᩓ཯ᛂ࡛⏺㠃࡟ཌ࠸ Nb3Sn ᒙࢆ⏕ᡂࡉࡏࡿࡓࡵࠊ኱ࡁࡃࡣෆ㒊 Sn ᣑᩓἲ࡟㢮ఝࡍࡿࠋࡇࡢ〇ἲ࡛ࡶࠊNb ⟶࡜⢊ᮎࡢ㛫࡟ Cu ⟶ࢆᤄධࡋࡓࡾࠊ⢊ᮎෆ㒊࡟ᑡ㔞ࡢ Cu ⢊ᮎࢆΰࡐࡓࡾ࡞
࡝ࠊCu ࡢຠᯝࡀ฼⏝ࡉࢀ࡚࠸ࡿࠋ
ෆ㒊 Sn ᣑᩓἲࡣࠊ」ྜࡍࡿཎᩱࡢᙧ≧ࡸศ㔞ࠊ㓄⨨ࡢ㐪࠸࡟ࡼࡗ࡚⣽ศ㢮ࡉࢀࠊNb ⟶ࡢෆഃ࡟

㸲㸫 5

ᅗ 11. RRP ἲ Nb3Sn ከⰺ⥺ᮦ㸦⇕ฎ⌮๓㸧ࡢࣇ࢕࣓ࣛࣥࢺ㒊ࡢᣑ኱෗┿[28]ࠋ
ᅗ 10. ࢳ࣮ࣗࣈἲ Nb3Sn ከⰺ⥺ᮦࡢ᩿㠃[26]ࠋ
ⷧ⫗ࡢ Cu ࡛そࢃࢀࡓ⣧ Sn Წ࠶ࡿ࠸ࡣᑡ㔞ࡢ Tiࡀῧຍࡉࢀࡓ Sn Წࢆᤄධࡍࡿ࡜ࢳ࣮ࣗࣈἲ࡜࿧
ࡤࢀ࡚࠸ࡿࠋᡃࡀᅜ࡛ࡣ᫛࿴㟁⥺࡛㛤Ⓨࡉࢀ࡚ࠊNIMS ࡀಖ᭷ࡍࡿࣁ࢖ࣈࣜࢵࢻ࣐ࢢࢿࢵࢺࡢ኱ཱྀ
ᚄ㉸ఏᑟ࣐ࢢࢿࢵࢺ㸦16T㸧࡟ࡶᛂ⏝ࡉࢀࡓࠋࡑ
ࡢᚋ࡟ྠ♫ࡣ Nb3Sn ⥺ᮦࡢ〇㐀࠿ࡽ᧔㏥ࡋࠊ⌧ᅾࡣᑠつᶍ࡛ࡣ࠶ࡿࡀ⡿ᅜ HyperTech Research♫࡞࡝࡛పࢥࢫࢺ㧗 Jc ⥺ᮦࡢೃ⿵࡜ࡋ࡚◊✲㛤Ⓨࡀ⥅⥆ࡉࢀࠊᅗ 10 ࡟♧ࡍࡼ࠺࡞ࣇ࢕࣓ࣛࣥࢺ
ᚄࡀẚ㍑ⓗ⣽࠸ከⰺ⥺ᮦࡶヨసࡉ࡚࠸ࡿ [26]ࠋࡲ
ࡓࠊ Cu ẕᮦ࡟」ᩘࡢ Nb ⰺࡀᇙࡵ㎸ࡲࢀࡓභゅᙧࣔࢪ࣮ࣗࣝࢆࠊྠࡌࡃභゅᙧࡢ Cu ⿕そ Sn ࣔࢪ࣮ࣗࣝࢆྲྀࡾᅖࡴࡼ࠺࡟㓄⨨࣭⤌ࡳୖࡆࡿ〇ἲࢆ DT㸦Distributed Tin㸧ἲ࡜࿧ࡧࠊ୕⳻㟁ᶵࡸᪧ᪥❧㟁⥺ࠊ⚄ᡞ〇㗰㸦ཬࡧࡑࡢࢢ࣮ࣝࣉ఍♫ࡢ
JASTEC㸧࡞࡝࡛◊✲㛤Ⓨࡀ㐍ࡵࡽࢀࡓࠋ⌧ᅾࡣ⚄ᡞ〇㗰ࢢ࣮ࣝࣉ࡛ᘬࡁ⥆ࡁ㛤Ⓨࡀ㐍ࡵࡽࢀ࡚࠸ࡿ[27]ࠋࡲࡓࠊⷧ࠸ Cu ࡛⿕そࡋࡓ Nb Წࢆࡓࡃࡉࢇ᮰ࡡࠊࡑࡢ୰ኸ࡟⣧ Sn Წࢆ㓄⨨ࡋ࡚እ࿘ࢆ
Nb ࣂࣜ࢔࡛そࡗࡓࣔࢪ࣮ࣗࣝࢆసᡂࡋࠊࡇࢀࢆ
」ᩘᮏ᮰ࡡࡿ〇ἲࢆ RRP㸦Restack-Rod Process㸧ἲ࡜࿧ࡧࠊ⡿ᅜ OST ♫㸦⌧ Bruker-OST ♫㸧࠿ࡽᥦ᱌ࡉࢀࡓ[28]ࠋᅗ 11 ࡟♧ࡍࡼ࠺࡟ࠊNb ࣂࣜ࢔࡛そࢃࢀࡓࣔࢪ࣮ࣗࣝࡀ 1 ࡘࡢ㉸ఏᑟࣇ࢕࣓ࣛࣥ
ࢺ࡟࡞ࡾࠊᑠࡉ࡞ࡓࡃࡉࢇࡢ Nb ⰺࡣ⇕ฎ⌮࡛
Nb3Sn ࡜࡞ࡗ࡚ࡍ࡭࡚ࡀࡘ࡞ࡀࡿࠋ㉸ఏᑟࣇ࢕ࣛ
࣓ࣥࢺᚄࡀ 50-100 ࣑ࢡࣟࣥ࡜኱ࡁࡃ࡞ࡿࡀࠊ4ࠋ
2Kࠊ15-16T ࡛ᴟࡵ࡚㧗࠸ Jc㸦㠀㖡㒊㸧ࡀᚓࡽࢀࡿࡇ࡜࠿ࡽࠊḢᕞཎᏊ᰾◊✲ᶵᵓ㸦CERN㸧ࡀಖ᭷ࡍࡿ LHC ຍ㏿ჾࡢ࢔ࢵࣉࢢ࣮ࣞࢻࡢࡓࡵࡢ㧗☢ሙ࣐ࢢࢿࢵࢺ⏝ᑟయ࡜ࡋ࡚㐺⏝ࡉࢀࡓࠋࡉࡽ࡟
CERN ࠿ࡽࡣࠊᩘᖺ๓࡟ LHC ຍ㏿ჾࡢḟୡ௦ᵓ᝿࡜ࡋ࡚࿘㛗 100km ࡢ㉸ᕧ኱෇ᙧຍ㏿ჾ㸦FCC㸧
ࡢᘓタィ⏬ࡀⓎ⾲ࡉࢀࡓ[29]ࠋFCC ࡟࠾ࡅࡿ㉸ఏᑟ࣐ࢢࢿࢵࢺ࡛ࡣࠊLHC ࡢಸࡢ኱ࡁࡉ࡜࡞ࡿ 16
T ࡢ☢ሙ㐠㌿ࢆ┠ᶆ࡜ࡋ࡚࠾ࡾࠊࡑࡇ࡟౑ࢃࢀࡿ
㉸ఏᑟ⥺ᮦ࡟ࡣ 1,500 A/mm2㸦4.2K, 6T㸧ࡶࡢᴟࡵ࡚኱ࡁ࡞ Jc ࡀᚲせ࡜ࡉࢀ࡚࠸ࡿ[30]ࠋ⌧ᅾࠊ ࡇࡢ᮲௳ࢆ‶ࡓࡍ㛗ᑻ㉸ఏᑟ⥺ᮦࡣ࡞ࡃࠊ௒ࡢ࡜ࡇࢁࠊRRP ἲࢆ௦⾲࡜ࡋࡓෆ㒊 Sn ᣑᩓἲ⥺ᮦࡀ᭷ຊೃ⿵࡜ࡋ࡚ᨵⰋࡀ㐍ࡵࡽࢀ࡚࠸ࡿࠋ౛࠼ࡤࠊ⥺ᮦ୰ࡢ Nb ⰺ࡟ Zr ࢆᚤ㔞ῧຍࡋࠊྠ᫬࡟⥺ᮦෆ㒊࡟ SnO2 ࢆྵ᭷ࡉࡏࡿࡇ࡜࡛኱ᖜ࡞ Jc ྥୖࡀᚓࡽࢀࡿ࡜࠸࠺ሗ࿌ࡀ࠶ࡿ[31]ࠋࡇࡢ⥺ᮦࢆ⇕ฎ⌮
ࡍࡿ࡜ࠊNb ⰺ୰ࡢ Zr ࡀඃඛ㓟໬ࡉࢀ࡚ᚤ⣽࡞
ZrO2 ࡀᙧᡂࡉࢀࠊࡑࢀࡀ Nb3Sn ⤖ᬗࡢ⢏ᡂ㛗ࢆᢚไࡋ࡚ Nb3Sn ࡢᚤ⣽໬࡟ᐤ୚ࡍࡿ࡜࡜ࡶ࡟ࠊ
ᚤ⣽࡞ ZrO2 ࡑࡢࡶࡢࡀ☢᮰ࡢࣆࣥṆࡵ࡜ࡋ࡚స
⏝ ࡍࡿ ࡜ㄝ᫂ ࡋ࡚ ࠸ࡿࠋ ࡲࡓ ࠊ⥺ᮦ ࡢෆ 㒊࡟
Gd2O3 ➼ࡢᴟప ࡛ࡢẚ⇕࡟኱ࡁ࡞ࣆ࣮ࢡࢆࡶ
ࡘ≀㉁ࢆྵࡲࡏ࡚ࠊ⥺ᮦ඲యࡢ ᗘୖ᪼ࢆ㜵࠸࡛Ᏻᐃᛶࢆᨵၿࡍࡿヨࡳࡶሗ࿌ࡉࢀ࡚࠸ࡿ[32]ࠋࡇࡢ
ࡼ࠺࡟ࠊ୺࡟㧗☢ሙ NMR ࣐ࢢࢿࢵࢺࡸࠊ᰾⼥ྜ
⅔ࡸ㧗࢚ࢿࣝࢠ࣮⢏Ꮚຍ㏿ჾ࡞࡝ࡢᕧ኱࡞ᅜ㝿ࣉ ࣟࢪ ࢙ࢡࢺ ࢆ㥑 ືຊ࡜ ࡋ࡚ ࠊ⌧ᅾ ࡶ㧗 ᛶ⬟
Nb3Sn ⥺ᮦࡢ◊✲㛤Ⓨࡀ⧞ࡾᗈࡆࡽࢀ࡚࠸ࡿࠋ
3.2. Nb3Al ⥺ᮦ
1958 ᖺࡢ࣋ࣝ◊࡛ࡢⓎぢᙜึࠊNb3Al ࡢ Tc ࡣ
17.5K ࡜ሗ࿌ࡉࢀ࡚ Nb3Sn ࡼࡾࡶప࠸࡜ぢ࡞ࡉࢀ࡚࠸ࡓࠋ࡜ࡇࢁࡀ 1969 ᖺࠊྠࡌࡃ࣋ࣝ◊ࡢ
Willens ➼ࡣࠊNb ࡜ Al ࢆΰྜࡋ࡚ᅽ⦰⢊యࢆస㸲㸫 6〇ࡋ࡚㧗࿘Ἴ࡛ 1,700Υࡢ㧗 ຍ⇕ࢆ⾜࠸ࠊḟ࠸࡛ 700Υࡢప ࡛ᆒ㉁໬⇕ฎ⌮ࢆ⾜࠺࡜ࠊ18.8 K࡜࠸࠺㧗࠸ Tc ࡀᚓࡽࢀࡿࡇ࡜ࢆሗ࿌ࡋࡓ[33]ࠋ໬
Ꮫ㔞ㄽ⤌ᡂẚࡢ Nb3Al ┦ࡀ㧗 ࡢࡳ࡛Ᏻᐃ┦࡛࠶ࡿࡇ࡜࡟⏤᮶ࡍࡿࠋ⩣ᖺ 1970 ᖺ࡟ࡣࠊ⡿ᅜ࣐ࢧࢳ࣮ࣗࢭࢵࢶᕤ⛉኱Ꮫࡢ Foner ➼ࡀ 4.2 K ࡛ࡢ
Bc2 ࡀ⣙ 30 T ࡛࠶ࡿࡇ࡜ࢆ☜ㄆࡋ[34]ࠊNb3Al ࡢඃࢀࡓ㧗☢ሙ≉ᛶࡀ♧ࡉࢀࡓࠋࡉࡽ࡟ 1980 ᖺ௦࡟࡞ࡗ࡚ࠊ⡿ᅜᶆ‽ᢏ⾡◊✲ᡤ㸦NIST㸧ࡢ Ekin ࠿ࡽ Nb3Al ࡢඃࢀࡓ⪏ࡦࡎࡳ≉ᛶࡀ♧ࡉࢀ࡚[35]ࠊ
㟁☢ຊࡀ㧗ࡲࡿ㧗☢ሙ኱ᆺ࣐ࢢࢿࢵࢺᛂ⏝࡟ྥࡅ࡚ Nb3Al ࡬ࡢᮇᚅࡀ኱ࡁࡃ⭾ࡽࡳࠊࡑࡢᐇ⏝⥺ᮦࡢⓏሙࡀᚅࡕᮃࡲࢀࡓࠋV3Ga ࡸ Nb3Sn ࡛ࡣࠊ஧ඖ⣔ࡢ┦஫ᣑᩓ࠿ࡽ Cu ࢆຍ࠼ࡓ୕ඖ⣔ࡢ཯ᛂ⤒㊰㸦ࣈࣟࣥࢬ࣮ࣝࢺ㸧࡟⨨ࡁ᥮࠼ࡿࡇ࡜࡛ A15
ᆺ໬ྜ≀ࡢ༢┦ࢆᚓࡿࡇ࡜ࡀ࡛ࡁࡓࡀࠊNb3Al ࡟ࡇࡢ๓౛ࡣ㏻⏝ࡋ࡞࠿ࡗࡓࠋNb ࡜ Al ࡢ஧ඖ⣔ࡢᣑᩓ཯ᛂ࡛ࡣࠊAl ࡢᣑᩓ㏿ᗘࡀ㐜࠸ࡓࡵࠊNb2Al
ࡸ NbAl3 ➼ࡢ㠀㉸ఏᑟ┦ࡀඃඛⓗ࡟⏕ᡂࡉࢀࡿࠊ
ࡉࡽ࡟ Cu ࢆຍ࠼ࡓ୕ඖ⣔࡛ࡶࡑࡢ཯ᛂ⤒㊰࡟ࡣ୕ඖ⣔ࡢ Ǎ ┦ࡸ C14 ┦㸦࣮ࣛ࣋ࢫ┦㸧ࡀ௓ᅾࡋ࡚
Nb3Al ࡢ⏕ᡂࡀ㜼ࡲࢀࡓ [36]ࠋᅗ 12 ࡟ Nb3Al ┦࡟⮳ࡿᣑᩓ⤒㊰㏵୰࡟Ꮡᅾࡍࡿྛ✀ࡢ୰㛫┦ࢆࡲ࡜ࡵࡓࠋࡑࡇ࡛ࠊNb ࡜ Al ࡢ஧ඖ⣔࡟࠾࠸࡚ࠊᙉไⓗ࡟ᣑᩓ㊥㞳ࢆ▷ࡋ࡚ Nb3Al ┦ࡢ⏕ᡂࢆ≺ࡗࡓ⥺ᮦ໬ࣉࣟࢭࢫࡀ㐍ࡵࡽࢀࡓࠋ 1975 ᖺࠊ࢖ࢱࣜ࢔ࡢ
Ceresara ࡽ࠿ࡽࡣࠊNb ࡜ Al ࡢⷧ࠸⟩ࢆ⣽࠸ CuᲬ࡟㔜ࡡᕳࡁࡋࠊࡑࢀࢆ Cu ⟶࡟ᤄධࡋ࡚ຍᕤࡍ
ࡿ᪉ἲࢆᥦ᱌ࡋࡓ[37]ࠋఙ⥺ຍᕤᚋ࡟ Al ⟩ࡢཌࡳࡣ 200 nm ࡲ࡛ⷧࡃ࡞ࡾࠊ850Υ⛬ᗘࡢప ⇕ฎ⌮࡛ࡶẚ㍑ⓗከࡃࡢ Nb3Al ┦ࡀ⏕ᡂࡉࢀࡿࡇ࡜ࢆぢฟࡋࡓࠋ⏕ᡂࡋࡓ Nb3Al ┦ࡣࠊప ᣑᩓ཯ᛂ࡛໬Ꮫ㔞ㄽ⤌ᡂẚ࠿ࡽࡎࢀ࡚࠸ࡿࡓࡵ 15.6 K ⛬ᗘࡢ Tc ࡛ࡣ࠶ࡗࡓࡀࠊ10 T ௨ୖࡢ㧗☢ሙୗ࡛
1,000 A/mm2 ௨ୖࡢ㧗࠸ Jc ࢆᚓࡿࡇ࡜ࡀ࡛ࡁࡓࠋ
ࡇࡢ」ྜຍᕤἲࡣࠊᚋ࡟ࢪ࢙࣮࣮ࣜࣟࣝἲ࡜࿧ࡤ
ࢀ࡚࠸ࡿࠋࡑࡢᚋࡢ 1980 ᖺ࡟᪥ᮏ኱Ꮫࡢ⛅὾Ⰻ
୕ࡽࡀ PIT ἲ[38]ࠊ1988 ᖺ࡟㔠ᒓᮦᩱᢏ⾡◊✲ᡤ㸦⌧ NIMS㸧ࡢ஭ୖᗮࡽࡀ RIT㸦Rod-In-Tube㸧ἲ[39] ࢆ 1989 ᖺ ࡟ ᮾ ໭ ኱ Ꮫ ࡢ ᩪ ⸨ ᰤ ࡽ ࡀ CCE
㸦Clad-Chip-Extrusion㸧ἲ[40]ࢆᥦ᱌ࡋࠊNb ࡜ Al
ࡢᣑᩓ㊥㞳ࢆ▷ࡃࡋ࡚ప ᣑᩓ཯ᛂࡉࡏࡿࡓࡵ
ࡢ」ྜຍᕤἲࡀ⥆ࠎ࡜᳨ウࡉࢀࡓࠋ࠸ࡎࢀࡢᡭἲ
ࡶᣑᩓ㊥㞳ࢆ▷ࡃࡍࡿ࡯࡝ Jc ࡣྥୖࡋࡓࠋࡇࢀ
ࡽࡢ」ྜຍᕤἲࡢෆࠊ㔞⏘ࡲ࡛㐍ࢇࡔࡢࡣ၏୍ࢪ
࢙࣮࣮ࣜࣟࣝἲ࡛ࠊ
ᡃࡀᅜ࡛ࡣఫ཭㟁ᕤࡀᅗ 13 ࡟♧ࡍ᮲㛗 16 km ࡢ Nb3Al ከⰺ⥺ᮦࡀ㛤Ⓨࡉࢀࠊᙜ᫬ࠊ⥲㛗 230 km㸦㔜㔞࡛ 1 ton㸧ࡢ㔞⏘ࡀ⾜ࢃࢀࡓ[41]ࠋࡇࡢ㔞⏘⥺ᮦࡢ㛤Ⓨࡣࠊ᪥ᮏཎᏊຊ◊✲ᡤ㸦⌧ QST㸧࡜࡜ࡶ࡟ ITER ࡬ࡢᛂ⏝ࢆ┠ᣦࡋ࡚ᐇ᪋ࡉࢀ࡚࠸ࡓࡀࠊ᭱⤊ⓗ࡟ࡑࡢᐇ⌧ࡣྔࢃࡎࠊ
ᙜ᫬ࡢ Nb3Al ከⰺ⥺ᮦࡢ㛤Ⓨࡣᛴ㏿࡟ࣇ࢙࣮ࢻ
࢔࢘ࢺࡋ࡚࠸ࡗࡓࠋ
ࡲࡓ Nb3Al ࡟ࡣࠊࡇࢀࡲ࡛࡟㏙࡭࡚ࡁࡓ A15┦ࡀᣑᩓ཯ᛂ࡛ᚓࡽࢀ࡟ࡃ࠸௚࡟ࠊ㧗࠸ Tc ࡀᚓࡽࢀࡿ໬Ꮫ㔞ㄽ⤌ᡂẚࢆࡶࡘ A15 ┦ࡣ 1980Υࡢ㧗 ࡛ ࡢࡳᏳ ᐃ࡛ ࠶ࡿ࡜ ࠸࠺ ≉ᚩࡀ ࠶ࡗ ࡓࠋ
NIMS ࡢ◊✲ࢢ࣮ࣝࣉ࡛ࡣࠊඛࡢᣑᩓἲ Nb3Al ⥺ᮦ࡜ࡣูࡢ⊂⮬ࡢ࢔ࣉ࣮ࣟࢳ࡛⥺ᮦ㛤Ⓨࡀ㐍ࡵࡽࢀ࡚ࡁࡓࠋ≉ᛶࡢࡼ࠸ A15 ┦ࢆᚓࡿࡓࡵ࡟㧗Cu
Cu-Al䠄䝤䝻䞁䝈䠅ྜ㔠䠄 CuSS 䠅
C14 Laves phase䠄 Nb(AlCu) 2 䠅P phase䠄Nb2AlCu䠅

Nb

Nb3Al

Nb2Al

NbAl3

Al

ᅗ 13. Nb ⟩࡜ Al ⟩ࢆ㔜ࡡᕳࡁࡍࡿࢪ࢙࣮ࣜࣟ
࣮ࣝἲ࡛సᡂࡉࢀࡓ Nb3Al ከⰺ⥺ᮦࡢ᩿㠃෗┿[41]ࠋ㯮Ⰽࡢ㒊ศࡀ Nb3Al ࡜࡞ࡿࢪ࢙ࣜ
࣮࣮ࣟࣝࣇ࢕࣓ࣛࣥࢺ࡛ẕᮦࡣᏳᐃ໬㖡ࠋ

ᅗ 12. Nb3Al ┦࡟⮳ࡿᣑᩓ⤒㊰㏵୰࡟Ꮡᅾࡍࡿ
ྛ✀ࡢ୰㛫┦ࠋ

㸲㸫 7

A15 Grain 1
Stacking Fault

GB
A15 Grain 2

Stacking Fault

GBᅗ 14. ᛴ⇕ᛴ෭ฎ⌮⿦⨨ࡢእほ෗┿[45]ࠋྑୖ࣎
ࣅࣥ࠿ࡽᕥୖ࣎ࣅࣥ࡟ NbAl ๓㥑య⥺ᮦࢆ㧗
㏿࡛ᕳࡁ᭰࠼ࡿࠋࡑࡢ㏵୰ࡢྑୗࡢ⣧㖡〇࢞࢖ࢻࣉ࣮࣮ࣜ࡜⟽ᙧ Ga ᾎࡢ㛫㸦⣙ 150mm㸧
࡛㏻㟁ຍ⇕࡜ᛴ෭ฎ⌮ࢆ㐃⥆ⓗ࡟⾜࠺ࠋᅗ 15. ᛴ⇕ᛴ෭ἲ Nb3Al ⥺ᮦࡢ┦ኚែᚋࡢ
Nb3Al ┦࡟ほᐹࡉࢀࡿ」㞧࡞᱁ᏊḞ㝗[47]㸬

⇕ฎ⌮ࡢไᚚࢆ≺ࡗࡓࣉࣟࢭࢫ㛤Ⓨࡀ⧞ࡾᗈࡆ
ࡽࢀࡓࠋ1985 ᖺ㡭࡟ࡣᡞྔ୍ṇࡽ࡟ࡼࡾࠊ㧗 ࡢ
NbAl ⼥యࢆ㧗㏿⛣ືࡍࡿຍ⇕ࡉࢀࡓ Cu ࢸ࣮ࣉࡢ⾲㠃࡟㐃⥆ⓗ࡟྿ࡁ௜ࡅ࡚ᛴ෭ࡍࡿᡭἲ [42]ࡀ
᳨ウࡉࢀࠊࡲࡓ 1987 ᖺ㡭࡟ࡣ⇃಴ᾈ᫂ࡽ࡟ࡼࡾ
Nb ࡜ Al ࡢ๓㥑య⥺ᮦࢆ㟁Ꮚࡸ࣮ࣞࢨ࣮➼ࡢ㧗࢚ࢿࣝࢠ࣮ࣅ࣮࣒࡛↷ᑕࡋ࡚㧗 ▷᫬㛫ࡢ⇕ฎ⌮ࢆ㐃⥆ⓗ࡟⾜࠺ᡭἲ[43]ࡀ᳨ウࡉࢀࡓࠋ࠸ࡎࢀࡶ㛗ᑻฎ⌮ࡀ㞴ࡋ࠸ၥ㢟ࡀ࠶ࡗࡓࠋ1990 ᖺ௦࡟࡞ࡗ
࡚ࠊ஭ୖᗮࡽ࡟ࡼࡾ㏻㟁ຍ⇕࡜ᾮయ㔠ᒓࡢ Ga ᾎᛴ෭ࢆ⤌ࡳྜࢃࡏࡓࠕᛴ⇕ᛴ෭ἲࠖࡀᥦ᱌ࡉࢀࡓ
[44]ࠋ㛗ᑻࡢ NbAl ๓㥑య⥺ࢆ౪⤥࣮ࣜࣝ࠿ࡽᕳྲྀ
࣮ࣜࣝ࡟ᕳࡁ᭰࠼࡞ࡀࡽࠊࡑࡢ㏵୰࡛┤ὶ㏻㟁ࡋ
࡚ 2,000Υ㏆ഐ࡟⮬ᕫຍ⇕ࡉࡏࠊᘬࡁ⥆ࡁᐊ ㏆
ഐࡢ Ga ᾎ࡟ᑟ࠸࡚ᛴ෭ࡍࡿ㐃⥆ฎ⌮⿦⨨ࡀ㛤Ⓨࡉࢀࡓࠋᅗ 6 ࡣᛴ⇕ᛴ෭⿦⨨ࡢእほ෗┿࡛࠶ࡿ[45]ࠋࡇࡢᛴ⇕ᛴ෭ฎ⌮࡛ࡣࠊ యᚰ❧᪉ᬗ㸦bcc㸧
ࡢ Nb ࡟ Al ࡀ㐣㣬࿴࡟ᅛ⁐ࡋࡓྜ㔠┦ࡀ⏕ᡂࡉࢀࡿࠋࡇࡢ㐣㣬࿴ᅛ⁐యࡣ Nb ࡜ Al ࡀ A15 ┦ࡢ໬Ꮫ㔞ㄽ⤌ᡂ࡜࡞ࡗ࡚࠾ࡾࠊᐊ ࡛ࡣᨃᏳᐃ┦࡛࠶ࡿࠋࡑࡇ࡛ 800Υ⛬ᗘࡢ㏣ຍ⇕ฎ⌮ࢆ⾜࠺࡜ࠊbcc ┦࠿ࡽ A15 ┦࡟┦ኚែࡍࡿࠋࡇࡢࡓࡵࠊ
ࠕᛴ⇕ᛴ෭ἲࠖࡣࠕᛴ⇕ᛴ෭࣭ኚែἲࠖ࡜ࡶ࿧ࡤࢀࡿࠋ
┦ኚែᚋࡢ Nb3Al ࡣࠊ඲యⓗ࡟ࡣ໬Ꮫ㔞ㄽẚ࡟㏆࠸⤌ᡂࡀ⥔ᣢࡉࢀ࡚࠸ࡿࠋࡋ࠿ࡋᚤどⓗ࡟ࡳࡿ࡜ࠊ⤖ᬗ⢏ෆ࡟ࡣ↓ᩘࡢ Al ⃰ᗘ࡟ᐩࢇࡔ✚ᒙḞ㝗ࡀᙧᡂࡉࢀࠊࡉࡽ࡟኱ഴゅࡢ⢏⏺࡜࡜ࡶ࡟ᑠഴ
ゅࡢள⢏⏺ࡶከࡃㄆࡵࡽࢀࡓ㸦ᅗ 15㸧[46]ࠋࡇࢀࡲ

࡛ࡢᣑᩓ⏕ᡂࡍࡿ A15 ᆺ㉸ఏᑟయ࡟☜ㄆࡉࢀࡿ᱁ᏊḞ㝗ࡣ⤖ᬗ⢏⏺ࡀ୺࡞ࡶࡢ࡛࠶ࡗࡓࠋࡇࡢࡼ
࠺࡞」㞧ୟࡘ㝵ᒙⓗ࡞᱁ᏊḞ㝗ᵓ㐀ࡀ᭷ຠ࡞ࣆ
ࣥṆࡵⅬ࡜ࡋ࡚స⏝ࡋ࡚࠸ࡿࡓࡵ࠿ࠊࡇࢀࡲ࡛ࡢ
ᣑᩓἲ Nb3Al ⥺ᮦࡸࣈࣟࣥࢬἲ Nb3Sn ⥺ᮦࡼࡾ᱁ẁ࡟㧗࠸ Jc ࡀᚓࡽࢀࡓࠋࡑࡢᐇ⏝໬ࡀᚅᮃࡉ
ࢀࠊᏳᐃ໬ࡢࡓࡵࡢ Cu ࡢ」ྜᢏ⾡ࡶ㛤Ⓨࡉࢀ࡚ࠊ㧗☢ሙ NMR ࡢෆᤄࢥ࢖ࣝࡸ㧗☢ሙຍ㏿ჾ⏝࣐ࢢࢿࢵࢺࡢࡓࡵࡢࣉࣟࢺࢱ࢖ࣉࡶ㛤Ⓨࡉࢀࡓࡀࠊ᭱
⤊ⓗ࡟ࡣᐇ⏝໬ࡢ᪥ࡢ┠ࢆぢࡿࡇ࡜ࡣ࡞࠿ࡗࡓ
[45]ࠋ≉ᛶࡣඃࢀࡿࡀࠊ㠀ᖖ࡟㧗ᗘ࡞ไᚚࡀᚲせ࡞⇕ฎ⌮ࡸᏳᐃ໬㖡ࢆ௜୚ࡍࡿࡓࡵ࡟≉Ṧ࡞ฎ⌮ࢆᚲせ࡜ࡍࡿࠋࡇࡢ」㞧ୟࡘ↹㞧࡞ࣉࣟࢭࢫ⮬㌟
ࡀᛴ⇕ᛴ෭ἲ Nb3Al ⥺ᮦࡢᐇ⏝໬ࡢ኱ࡁ࡞ቨ࡜
࡞ࡗࡓࠋ᭱㏆ࠊNIMS ࡢ⳥ụ❶ᘯࡽ࡟ࡼࡾ㧥ࡢẟࡼࡾࡶ⣽࠸ࢪ࢙࣮࣮ࣜࣟࣝἲ Nb3Al ᴟ⣽⥺ᮦࡢ㛤Ⓨࡀ㛤ጞࡉࢀୡ⏺ⓗ࡟ὀ┠ࢆ㞟ࡵ࡚࠸ࡿ㸦ᅗ 16㸧[47]ࠋ
୍⯡ⓗ࡟ Nb3Al ࡸ Nb3Sn ➼ࡢ໬ྜ≀⣔㉸ఏᑟ⥺ᮦࡣࠊఙ⥺ຍᕤࡋࡓᚋ࡟⇕ฎ⌮ࢆ⾜ࡗ࡚㉸ఏᑟ┦ࢆ⏕ᡂࡉࡏࡿࡓࡵࠊ⇕ฎ⌮ᚋࡢ⥺ᮦࡣ⬤ࡃ⡆༢࡟ᢡࢀࡿࠋࡑࡢࡓࡵࠊࢥ࢖ࣝ໬ࡣఙ⥺ຍᕤᚋ࡟ࡲࡎ
ᕳࡁ⥺ࡋࠊࡑࡢᚋ࡟⇕ฎ⌮ࢆ⾜࠺ Wind & Reactἲࡀᗈࡃ㐺⏝ࡉࢀ࡚࠸ࡿࠋࡇࡢ᪉ἲ࡟࠾࠸࡚ࡣࠊ
⇕ฎ⌮࡟⪏࠼ࡿ࢞ࣛࢫࡸࢭ࣑ࣛࢵࢡࢫ〇ࡢ㧗౯࡞⤯⦕ᮦࢆ౑ࢃ࡞ࡅࢀࡤ࡞ࡽࡎࠊࡲࡓ⇕ฎ⌮᫬࡟⥺ᮦࡢ⇕⭾ᙇཬࡧ཰⦰࡟ࡼࡗ࡚ࢥ࢖ࣝࡢᕳࡁ⦆
ࡳࡸ㟁Ẽⓗ࡞▷⤡ࡀⓎ⏕ࡍࡿ࡞࡝ࠊᩘከࡃࡢၥ㢟

A15
Grain 3㸲㸫 8

200 nmᅗ 16. እᚄࡀ 30 ࣑ࢡࣟࣥࡢࢪ࢙࣮࣮ࣜࣟࣝἲ
Nb3Al ᴟ⣽⥺ᮦ࡜እᚄࡀ 100 ࣑ࢡࣟࣥࡢ㧥ࡢẟࢆẚ㍑ࡋࡓእほ෗┿[47]㸬
Ⅼࡀᣦ᦬ࡉࢀ࡚࠸ࡿࠋ⌧ᅾᬑཬࡋ࡚࠸ࡿ MRI ࡸᘓタࡀ㐍ࡵࡽࢀ࡚࠸ࡿࣜࢽ࢔࣮ࣔࢱ࣮࣮࢝ࡢ㉸ఏᑟ☢▼࡟ࡣ Nb-Ti ྜ㔠⥺ᮦࡀ౑ࢃࢀ࡚࠸ࡿࡀࠊ
Nb-Ti ྜ㔠ࡣఙ⥺ຍᕤᚋࡢ≧ែ࡛㉸ఏᑟ⥺ᮦ࡜ࡋ࡚ྲྀࡾᢅ࠸࡛ࡁࠊୟࡘ෭㛫࡛⮬ᅾ࡟ረᛶኚᙧࡍࡿ
ࡇ࡜ࡶྍ⬟࡛࠶ࡿࠋᕳࡁ⥺ᚋࡢ⇕ฎ⌮ࡣ୙せ࡞ࡓࡵ࡟Ᏻ౯࡞᭷ᶵ⤯⦕ᮦࡀ౑࠼࡚ࠊᕳࡁ⦆ࡳࡀⓎ⏕ࡍࡿࡇ࡜ࡶ࡞࠸ࠋࡇࢀ࡟ࡼࡾࠊ㧗࠸☢ሙ⢭ᗘࢆࡶࡗࡓ㉸ఏᑟ࣐ࢢࢿࢵࢺࡀᏳ౯࡟〇㐀ࡉࢀ࡚࠸ࡿࠋ
ࡶࡋࠊNb-Ti ྜ㔠ࡼࡾ㧗ᛶ⬟࡞໬ྜ≀⣔㉸ఏᑟࡀ
Nb-Ti ྜ㔠⥺ᮦ࡜ྠ➼ࡢࣁࣥࢻࣜࣥࢢ࡛ྲྀࡾᢅ࠺
ࡇ࡜ࡀ࡛ࡁࢀࡤࠊࡑࡢᐇ⏝໬ࡣ୍Ẽ࡟ຍ㏿ࡉࢀࡿࡔࢁ࠺ࠋ໬ྜ≀⣔㉸ఏᑟ⥺ᮦࢆࣇࣞ࢟ࢩࣈࣝ࡟ࡍ
ࡿ࡟ࡣࠊග㏻ಙ࡛౑ࢃࢀࡿࢢࣛࢫࣇ࢓࢖ࣂ࣮ࡢࡼ
࠺࡟⥺ᚄࢆᴟࡵ࡚⣽ࡃࡍࢀࡤ࠸࠸ࠋ⪏ࡦࡎࡳ≉ᛶ࡟ඃࢀࡿ Nb3Al ࡣᶵᲔⓗ࡞᭤ࡆ࡟ᙉ࠸ࠋࡲࡓࠊ⣽ᚄ࡜࡞ࡿࡇ࡜࡛㸯ᮏ࠶ࡓࡾࡢ㏻㟁ᐜ㔞ࡀపୗࡍࡿၥ㢟ࡀ࠶ࡿࡀࠊᴟ⣽⥺ࢆ᮰ࡡ࡚᧍ࡿࡇ࡜࡛㟁ὶᐜ㔞ࢆ⡆༢࡟ቑຍ࡛ࡁࠊࡲࡓ᮰ࡡ࡚ࡶ⣲⥺㛫ࡣࡃࡗࡘ࠸࡚࠸࡞࠸ࡢ࡛ྍ࡜࠺ᛶࡀຎࡿࡇ࡜ࡶ࡞࠸ࠋ
ᚑ᮶ࡢࣔࣀࣜࢫᆺከⰺ⥺ᮦࡼࡾࡶࢶ࢖ࢫࢺࣆࢵ
ࢳࢆ▷ࡃࡍࡿࡇ࡜ࡀ࡛ࡁࠊࡲࡓ᮰ࡡࡓ㝿ࡢ⣲⥺㛫ࡢ⤖ྜࡶᑠࡉࡃࡍࡿࡇ࡜ࡀᐜ᫆࡜࡞ࡗ࡚஺ὶᦆ
ኻࡢ኱ᖜ࡞పῶ࡜࠸࠺ຠᯝࡶᮇᚅࡉࢀࡿࠋᅗ 17ࡣࠊ᫖ᖺ㸦2021 ᖺ㸧࡟⳥ụ࠿ࡽᅜ㝿☢▼ᢏ⾡఍㆟
㸦MT27㸧࡛Ⓨ⾲ࡉࢀࡓ⤱⣒㸦እᚄ 20 ࣑ࢡࣟࣥ㸧ࡼࡾࡶ⣽࠸እᚄࡀ 17 ࣑ࢡࣟࣥࡢ㉸ᴟ⣽ Nb3Al ㉸ఏᑟ⥺ᮦࡢ᩿㠃෗┿࡛࠶ࡿ[48]ࠋᏳᐃ໬࡟ᐤ୚ࡍࡿ
↓㓟⣲㖡⟶ࡢෆ㒊࡟ࠊྠࡌࡃ↓㓟⣲㖡ࣟࢵࢻࡢ࿘
ᅖ࡟ Nb ⟩࡜ Al ⟩ࢆ㔜ࡡᕳࡁࡋࡓ✚ᒙయࡀ᱁⣡ࡉࢀ࡚࠸ࡿࠋ࠾ࡑࡽࡃୡ⏺࡛᭱ࡶ⣽࠸␗✀㔠ᒓࡢ」ྜຍᕤ⥺ᮦ࡛࠶ࡿࠋᘬࡁ⥆ࡁ᭦࡞ࡿᴟ⣽໬࡜㛗ᑻ໬ࠊࡑࡋ࡚㧗 Jc ໬ࡢྲྀࡾ⤌ࡳࡀ⾜ࢃࢀ࡚࠸ࡿࠋ

4. 㖡㓟໬≀⣔⥺ᮦ
4.1. Bi ⣔⥺ᮦ㸦Bi-2212 ཬࡧ Bi-2223㸧
1986 ᖺࠊࢫ࢖ࢫ IBM ࢳ࣮ࣗࣜࢵࣄࡢ Bednorz
࡜ Müller ࡟ࡼࡿ Tc ࡀ⣙ 30K ࡢ㖡㓟໬≀㉸ఏᑟయࡢⓎぢࡣ[49]ࠊୡ⏺ⓗ࡞ࣇ࢕࣮ࣂ࣮ࢆᕳࡁ㉳ࡇࡋ࡚ࠊࡼࡾ Tc ࡢ㧗࠸᪂≀㉁ࢆồࡵࡓᐆ᥈ࡋࡀάⓎ࡟⾜ࢃࢀࡓࠋ⩣ᖺࡢ 1987 ᖺ࡟ࡣࠊ⡿ᅜࣄ࣮ࣗࢫ
ࢺࣥ኱Ꮫࡢ C. W. Chu ࡽࡢ◊✲ࢢ࣮ࣝࣉࡀᾮయ❅⣲ᗘ㸦77K㸧ࢆ㉸࠼ࡿ Tc ࢆ♧ࡍ Y-Ba-Cu-O ࢆⓎぢࡋ[50]ࠊࡇࡢ⩣ᖺࡢ 1988 ᖺ࡟ࡣ㔠ᒓᮦᩱᢏ⾡◊✲ᡤ㸦⌧ NIMS㸧ࡢ๓⏣ᘯࡽࡀࠊึࡵ࡚ 100K
ࢆ㉸࠼ࡿ Tc ࢆ♧ࡍ Bi-Sr-Ca-Cu-O ࢆⓎぢࡋࡓ
[51]ࠋⓎぢᙜึࡢㄽᩥ࡛ࡣ஧ẁ㝵ࡢ㉸ఏᑟ㌿⛣᭤⥺ࡀⓎ⾲ࡉࢀࠊ
ᚋ࡟ Tc ࡀ⣙ 110K ࡢ Bi2Sr2Ca2Cu3Ox
㸦Bi-2223㸧┦[52]࡜ࠊ⣙ 85K ࡢ Bi2Sr2Ca1Cu2Ox
㸦Bi-2212㸧┦[53]࡛࠶ࡿࡇ࡜ࡀุ᫂ࡍࡿࠋࡑࡢ௚࡟
ࡶ Bi2Sr2Cu1Ox㸦Bi-2201㸧┦[54, 55]ࡶ Bi ⣔࡜ࡋ࡚ศ㢮ࡉࢀࡿࡀࠊTc ࡣ⣙ 20K ࡜ప࠸ࠋࡇࢀࡽ㸱✀㢮ࡢ Bi ⣔㉸ఏᑟయ࡛ࡣࠊ
Tc ࡢ㧗࠸ Bi-2223 ࡜ Bi2212 ࡢ⥺ᮦ໬ࡀୡ⏺ⓗ࡟㐍ࡵࡽࢀࡓࠋ࠸ࡎࢀࡶ
㔠ᒓ⟶࡟⢊ᮎࢆ඘ሸࡍࡿ PIT ἲࡀ୍⯡ⓗ࡞⥺໬ࣉࣟࢭࢫ࡜ࡋ࡚㐺⏝ࡉࢀ࡚࠸ࡿࠋ㔠ᒓ⟶࡟⣧ Ag
ᅗ 17. እᚄ 17 ࣑ࢡࣟࣥࡢࢪ࢙࣮࣮ࣜࣟࣝἲ
Nb3Al ㉸ఏᑟ⥺ᮦࡢ᩿㠃෗┿㸬⅊ⰍࡢẕᮦࡣᏳᐃ໬㖡[48]㸬

࠶ࡿ࠸ࡣ Ag ྜ㔠ࡀ⏝࠸ࡽࢀࡿࠋ㧗౯࡟ࡶ㛵ࢃࡽ
ࡎ Ag ࡀ⏝࠸ࡽࢀࡿࡢࡣࠊ඘ሸࡋࡓ㓟໬≀⢊ᮎ࡜ࡣ཯ᛂࡏࡎࠊୟࡘࠊ኱Ẽ୰㸦࠶ࡿ࠸ࡣ㓟⣲ࢆྵࡴ

㸲㸫 9

ᅗ 18. Bi ⣔㉸ఏᑟయࡢ⤖ᬗᵓ㐀[56]㸬

ᅗ 19. Ag ࢩ࣮ࢫ Bi-2212 ከⰺ⥺ᮦࡢ⇕ฎ⌮ᚋࡢ㉸ఏᑟࣇ࢕࣓ࣛࣥࢺ[58]ࠋ㞺ᅖẼ୰㸧࡛⇕ฎ⌮ࡋ࡚ࡶ㔠ᒓ⮬㌟ࡣ㓟໬ࡋ࡚࣎཯ᛂᚋࡢ⤖ᬗ⤌⧊ࡣࡉࡽ࡟」㞧࡟࡞ࡿࠋᚑࡗ࡚ࠊ

ࣟ࣎ࣟ࡟࡞ࡽࡎ࡟㓟⣲ࢆ㏻㐣ࡉࡏ࡚඘ሸ⢊ᮎ࡟⤖ᬗᡂ㛗࡜ᅽᘏࢆ஺஫࡟⧞ࡾ㏉ࡋ࡚ᶵᲔⓗ࡟⤖㓟⣲ࢆ౪⤥࡛ࡁࡿࡇ࡜ࡀ୺࡞⌮⏤࡛࠶ࡿࠋࡲࡓࠊ

ᬗ᪉఩ࢆ▹ṇࡍࡿᡭἲࡀ࡜ࡽࢀࠊ⥺ᮦࡣᖹⷧࡢࢸ

㖡㓟໬≀㉸ఏᑟయࡣ CuO2 㠃ࡀ⤯⦕ᒙ࡟ᣳࡲࢀࡓ

࣮ࣉᙧ≧࡜࡞ࡿࠋࡋ࠿ࡋࠊࡇࡢ⇕ฎ⌮࡜ᅽᘏࡢ⤌ᒙ≧ࡢ⤖ᬗᵓ㐀ࢆᣢࡕ㸦ᅗ 18㸧[56]ࠊ㉸ఏᑟ㟁ὶࡣࡳྜࢃࡏࡔࡅ࡛ࡣ኱Ẽ୰࡛⇕ฎ⌮ࡍࡿ࡜ࠊᯈ≧⤖CuO2 㠃࡟ᖹ⾜㸦c ㍈࡟ᆶ┤᪉ྥ㸧࡟ὶࢀࡸࡍ࠸ࠋ

ᬗࡣࣛࣥࢲ࣒࡟ᡂ㛗ࡋ࡚✵㝽ࡢከ࠸⤌⧊࡜࡞ࡿࠋ

⤖ᬗᡂ㛗ࡶ␗᪉ⓗ࡛ᯈ≧⤖ᬗࡀ c ㍈࡟ᆶ┤࡞᪉ྥࡑࡇ࡛ࠊ⣙ 300 Ẽᅽࡢ࢞ࢫᅽ࡛ຍᅽ↝ᡂࡍࡿࡇ࡜

࡟ᡂ㛗ࡋࡸࡍ࠸ࠋᚑࡗ࡚ࠊ㔠ᒓ⟶ࡢෆ㒊࡛ࡑࢀࡒ࡛኱ᖜ࡟✵㝽ࢆ↓ࡃࡍࡇ࡜ࡀ࡛ࡁࠊJc ࡀ኱ᖜ࡟ྥ

ࢀࡢ⤖ᬗࡀࣛࣥࢲ࣒࡞᪉ྥ࡟ᡂ㛗ࡍࡿ࡜ࠊᯈ≧⤖ୖࡋࡓ㸦ᅗ 20㸧[59]ࠋࡉࡽ࡟⥺ᮦ〇㐀ࡢṌ␃ࡲࡾࡶᬗࡢ㛫࡛༑ศ࡞⤖ྜ㠃ࡀᚓࡽࢀࡎࠊࡲࡓከᩘࡢ኱

ྥୖ࡛ࡁࡓࡇ࡜࡛ࠊBi-2223 ⥺ᮦࡢᕤᴗ〇ရ࡜ࡋࡁ࠸✵㝽ࡶ࡛ࡁࡸࡍࡃ࡞ࡗ࡚⢊ᮎ඘ሸ㒊࠶ࡓࡾ

࡚ࡢ㊥㞳ࡀ୍Ẽ࡟⦰ࡲࡗࡓࠋBi-2223 ⥺ᮦࡣࢸ࣮ࡢ Jc ࡀᑠࡉࡃ࡞ࡿࠋᚑࡗ࡚ࠊ㧗࠸ Jc ࢆᚓࡿ࡟ࡣ

ࣉᑟయ࡜ࡋ࡚ఫ཭㟁ᕤ࡛〇㐀㈍኎࡞ࡽࡧ࡟㛤Ⓨᯈ≧⤖ᬗࡢྥࡁࢆࡑࢁ࠼࡚㓄ྥࡉࡏࡿ⤌⧊ไᚚࡀ㐍ࡵࡽࢀ࡚࠸ࡿࠋᇶᮦࡀᰂࡽ࠿࠸㖟࡛࠶ࡿࡇ࡜ࡀᚲせ࡜࡞ࡿࠋణࡋࠊ⤖ᬗ㓄ྥᛶࡀ㧗ࡲࡿ࡯࡝ࠊ

࠿ࡽࠊᙉᗘࢆ㧗ࡵࡿࡓࡵ࡟ⷧ࠸ Ni ྜ㔠ࡸ Cu ྜ㉸ఏᑟ≉ᛶࡢ␗᪉ᛶࡶᙉࡃ࡞ࡾࠊc ㍈࡟ᖹ⾜࡞☢

㔠ࢸ࣮ࣉࢆ୧㠃࡟ᙇࡾ௜ࡅ࡚⿵ᙉࡉࢀ࡚࠸ࡿ[60]ࠋ

ሙࡀ༳ຍࡉࢀࡿ࡜ Jc ࡣᑠࡉࡃ࡞ࡿࡢ࡛ὀពࡀᚲ

ࡇࢀࡽ㧗ᙉᗘ Bi-2223 ࢸ࣮ࣉ⥺ᮦࡣࠊNIMS ࡢ

せ࡛࠶ࡿࠋ⤖ᬗ㓄ྥࡉࡏࡿᡭἲࡣ Bi-2212 ࡜ Bi-

1020 MHz-NMR ⏝࣐ࢢࢿࢵࢺ [59]ࡸᮾ໭኱Ꮫࡢ

2223 ࡜࡛ᑡࡋ␗࡞ࡿࠋBi-2212 ࡛ࡣࠊ㒊ศ⁐⼥ࡉࡏ࡚෭༷㐣⛬࡛㖟ࢩ࣮ࢫ࡜ࡢ⏺㠃࡟ἢࡗ࡚⤖ᬗࡀᡂ㛗ࡍࡿࠋᚑࡗ࡚ࠊከⰺ⥺ᮦ࡜ࡍࡿࡇ࡜࡛⢊ᮎ඘ሸ㒊ࡀ⊃ࡃ࡞ࢀࡤࠊ⤖ᬗࡣ⥺ᮦࡢ㛗ᡭ᪉ྥ࡟ྥ
࠿ࡗ࡚࠶ࡿ⛬ᗘࡣᥞࡗ࡚ᡂ㛗ࡍࡿ[57]ࠋBi-2212 ⥺ᮦཬࡧ Bi-2223 ⥺ᮦࡢ࠸ࡎࢀࡶከⰺᵓ㐀࡛〇㐀ࡉࢀ࡚࠸ࡿࡀࠊ⇕ฎ⌮ᚋࡣᅗ 19 ࡟♧ࡍࡼ࠺࡟⤖ᬗᡂ㛗࡟ࡼࡾ㉸ఏᑟࣇ࢕࣓ࣛࣥࢺࡣ⤖ྜࡍࡿ≧ែ࡜࡞ࡿࡢ࡛[58]ࠊᮏ᮶ࡢ㟁☢Ẽⓗ࡞ᦆኻపῶࢆ┠ⓗ࡜ࡋࡓࡶࡢ࡛ࡣ࡞࠸ࠋࡲࡓࠊBi-2223 ࡣ Bi-2212
ࢆ๓㥑య࡜ࡋࡓໟᬗ཯ᛂ࡛⤖ᬗᡂ㛗ࡀ㐍ࡴࡓࡵࠊ

ᅗ 20. Bi-2223 ࢸ࣮ࣉ⥺ᮦࡢຍᅽ↝ᡂࡢຠᯝ(a)኱Ẽ↝ᡂ, (b) ຍᅽ↝ᡂ[58]ࠋ㸲㸫 10↓෭፹ࡢ 25T ㉸ఏᑟ࣐ࢢࢿࢵࢺࡢ᭱ෆᒙࢥ࢖ࣝ

Tc ࡀᚓࡽࢀࡿ[67]ࠋᙜึࠊBi ⣔࡜ྠᵝ࡟ Ag ⟶ࢆ

[61]࡞࡝ࠊ᪤࡟࠸ࡃࡘ࠿ࡢᛂ⏝஦౛ࡶ࠶ࡿࠋ

⏝࠸ࡓ PIT ἲ࡟ࡼࡿ⥺ᮦ໬࡟ྲྀࡾ⤌ࡲࢀࡓࠋ㖡㓟

୍᪉ࠊBi-2212 ⥺ᮦࡣ Bi-2223 ⥺ᮦࡼࡾ Tc ࡀ໬≀⣔≉᭷ࡢᒙ≧ࡢ⤖ᬗᵓ㐀࡛㉸ఏᑟ≉ᛶ࡟␗ప࠸ࡀࠊᴟప ࡛ࡢ Bc2 ࡀ㧗࠸ࡇ࡜࠿ࡽࠊᾮయ࣊

᪉ᛶࡣ࠶ࡿࡀࠊBi ⣔࡜ࡣ␗࡞ࡾ⢏≧⤖ᬗ࡛࠶ࡿࡇ

࣒ࣜ࢘෭༷ࡢ㧗☢ሙ࣐ࢢࢿࢵࢺ࡬ࡢᛂ⏝ࡀᮇᚅ࡜࠿ࡽ⤖ᬗᡂ㛗ࢆ฼⏝ࡋࡓࡾᶵᲔⓗᅽᘏࢆ฼⏝ࡉࢀ࡚࠸ࡿࠋBi-2212 ࡟࠾࠸࡚ࡶຍᅽ↝ᡂἲࡣ Jc

ࡋࡓࡾࡋ࡚⤖ᬗ㓄ྥࡉࡏࡿࡇ࡜ࡀ࡛ࡁࡎࠊప࠸ Jc

ࢆ㧗ࡵࡿࡓࡵ࡟ᴟࡵ࡚᭷ຠ࡛࠶ࡿ[62]ࠋࡲࡓ᭱㏆࡛ࡋ࠿ᚓࡽࢀ࡞࠿ࡗࡓࠋࡉࡽ࡟ࠊ㉸ఏᑟ㟁ὶࢆᢸ࠺ࡣࢼࣀࢫࣉ࣮ࣞἲ࡟ࡼࡿཎᩱ⢊ᮎࡢ㉸ᚤ⣽໬ࡀ

CuO2 㠃ࢆ⥺ᮦࡢ㛗ᡭ᪉ྥ࡟ᥞ࠼ࡿࡔࡅ࡛࡞ࡃࠊ

ᅗࡽࢀ࡚ࠊ㉸ఏᑟ┦࠶ࡓࡾࡢ Jc ࡀ 4.2K ཬࡧ 15T

㠃ෆࡢഴゅࡶᥞ࠼࡚஧ḟඖ㸦୕ḟඖ㸧࡟㓄ྥࡉࡏ

࡛ࡣ 6,640A/mm2ࠊ30T ࡛ࡣ 4,670A/mm2 ࡜㠀ᖖࡿᚲせࡀ࠶ࡿࠋᅗ 21 ࡟♧ࡍࡼ࠺࡟ࠊ㠃ෆࡢഴゅ࡟㧗࠸್ࡀሗ࿌ࡉࢀ࡚࠸ࡿ[63]ࠋ㖡㓟໬≀⣔㉸ఏᑟ

ࡀ 5 ᗘࡎࢀࡿ࡜ Jc ࡣ࠾ࡼࡑ୍᱆ῶᑡࡋ࡚ࡋࡲ࠺

⥺ᮦࡢ୰࡛ࡣ၏୍࡟୸⥺ᮦ࡜ࡋ᳨࡚ウࡀ㐍ࢇ࡛[68]ࠋࡑࡢࡓࡵࠊᚑ᮶ࡢ୍⯡ⓗ࡞⥺ᮦ໬ᢏ⾡࡛࠶ࡿ࠸ࡿࡓࡵࠊ㧗࢚ࢿࣝࢠ࣮≀⌮ࡢศ㔝࠿ࡽࡣḟୡ௦ᘬᢤࡁຍᕤἲࡢ㐺⏝ࡀ㞴ࡋࡃࠊ༢⤖ᬗᇶᯈୖ࡟࢚

ࡢ㧗☢ሙຍ㏿ჾ⏝☢▼⏝ࣛࢨࣇ࢛࣮ࢻࢣ࣮ࣈࣝ

ࣆࢱ࢟ࢩࣕࣝᡂ㛗ࡉࡏࡿࡼ࠺࡞ᡂ⭷ࣉࣟࢭࢫ࡟

ࡢヨసࡸ◊✲ࡀ࣮ࣟࣞࣥࢫࣂ࣮ࢡ࣮ࣞ◊✲ᡤࡸࡼࡿ⥺ᮦ໬ࡀ㐍ࡵࡽࢀࡓ[69]ࠋࣁࢫࢸࣟ࢖࡞࡝ࡢ㔠⡿ᅜࣇ࢙࣑ࣝᅜ❧ຍ㏿ჾ◊✲ᡤ࡛㐍ࡵࡽࢀ࡚࠸

ᒓࢸ࣮ࣉࡢୖ࡟ᣑᩓ㞀ቨ࡜࡞ࡿࣂࢵࣇ࢓࣮ᒙࢆ

ࡿ[64, 65]ࠋᡃࡀᅜ࡛ࡣ᫛࿴㟁⥺࡛ Bi-2212 ⥺ᮦࡢヨ⤖ᬗ㓄ྥࡉࡏ࡚ᡂ⭷ࡋࠊࡑࡢ⾲㠃࡟㉸ఏᑟ⭷ࢆ࢚స࡜㛤Ⓨࡀ⾜ࢃࢀ࡚࠸ࡓࡀࠊ⌧ᅾࡣṧᛕ࡞ࡀࡽ஦

ࣆࢱ࢟ࢩࣕࣝᡂ㛗ࡉࡏࡿࠋ㸰ẁ㝵ࡢᡂ⭷ฎ⌮ࡀ㐃ᐇୖ୰Ṇࡉࢀ࡚࠸ࡿ≧ἣ࡛࠶ࡿࠋ⡿ᅜ࡛ࡣᪧ OST⥆ⓗ࡟⾜ࢃࢀࠊ㸯ẁ┠ࡢࣂࢵࣇ࢓࣮ᒙࡢᡂ⭷ࡣ♫㸦⌧ Bruker-OST ♫㸧࡛ᘬࡁ⥆ࡁ〇㐀㈍኎ࡀ⥔IBAD㸦Ion Beam Assisted Deposition㸧ἲ࡜࿧ࡤᣢࡉࢀ࡚࠸ࡿࠋ

ࢀ࡚࠸ࡿࠋ⤖ᬗࡢ<111>᪉ྥ࡟ᑐࡋ࡚ᩳࡵ 55 ᗘࡢ<111>᪉ྥ࠿ࡽ Ar ࢖࢜ࣥࣅ࣮࣒ࢆ↷ᑕࡋ࡞ࡀࡽ

4.2. ᕼᅵ㢮⣔⥺ᮦ㸦RE-123㸧YSZ㸦ZrO2:Y2O3㸻92:8㸧ࢆࢫࣃࢵࢱ⵨╔ࡍࡿ࡜ࠊึࡵ࡚ᾮయ❅⣲ ᗘ㸦77K㸧ࢆ㉸࠼ࡿ⣙ 90K ࡢࣛࣥࢲ࣒㓄ྥࡢᇶᮦୖ࡟≉ᐃ᪉ྥࡢ YSZ ⤖ᬗ⢏

Tc ࢆࡶࡘ Y ⣔㉸ఏᑟయ㸦YBa2Cu3Ox㸧ࡣࣄ࣮ࣗࡀ㑅ᢥⓗ࡟ሁ✚ࡋࡓ⤖ᬗ㓄ྥ⭷ࡀᙧᡂࡉࢀࡿࠋࡑ

ࢫࢺࣥ኱Ꮫࡽࡢ◊✲ࢢ࣮ࣝࣉ࡟ࡼࡾⓎぢࡉࢀࡓࡢ⌮⏤࡜ࡋ࡚ࠊ࢖࢜ࣥࢳࣕࢿࣜࣥࢢ࡛࢚ࢵࢳࣥࢢ

[66]ࠋࡇࡢ㉸ఏᑟయࡣࠊY ࢧ࢖ࢺࢆ Nd ࠿ࡽ Lu ࡲ࣮ࣞࢺ࡟ᕪࡀ⏕ࡲࢀࠊࢳࣕࢿࣜࣥࢢ᪉఩ࡢ⤖ᬗ⢏࡛ࡍ࡭࡚ࡢᕼᅵ㢮ඖ⣲࡟⨨ࡁ᥮࠼ࡿࡇ࡜ࡀ࡛ࡁࠊ

ࡀṧ␃ࡍࡿ࡜࠸࠺⪃࠼᪉ࡀ࠶ࡿ[70]ࠋ᭱㏆࡛ࡣ YSZ୍㒊ࢆ㝖࠸࡚ྠࡌᵓ㐀㸦RE-123㸧࡛ 85㹼95K ࡢࡼࡾ㧗㏿ᡂ⭷ࡀྍ⬟࡞ MgO ࡀࣂࢵࣇ࢓࣮ᒙ࡜ࡋ
࡚⏝࠸ࡽࢀ࡚࠸ࡿ [71]ࠋࡑࡢᚋࡢ㸰ẁ┠ࡢ RE-123
ᒙࡣ PLD㸦Pulsed Laser Deposition㸧ἲ [72] ࡸ
TFA-MOD 㸦 Trifluoro Acetates-Metal Organic

ᅗ 21. Y-123 ⤖ᬗⷧ⭷ࡢ⤖ᬗ⢏⏺ࡢഴゅ࡜
Jc ࡢ㛵ಀ[68]ࠋ

ᅗ 22. RE-123 ࢸ࣮ࣉ⥺ᮦࡢᵓ㐀[71]ࠋ

㸲㸫 11

Deposition 㸧 ἲ [73] ࠊ MOCVD 㸦 Metal Organicࡵࡿࡓࡵࡢ㉸ఏᑟ☢▼࡟ RE-123 ࢸ࣮ࣉ⥺ᮦࢆ✚Chemical Vapor Deposition㸧ἲ[74]࡞࡝࡛㐃⥆ᡂᒙࡋࡓ኱ᐜ㔞ࢣ࣮ࣈࣝ࡟ࡼࡿࣃࣥࢣ࣮࢟ᆺࢥ࢖

⭷ࡉࢀ࡚࠸ࡿࠋᅗ 20 ࡣ᭱㏆ࡢ RE-123 ࢸ࣮ࣉ⥺ࣝ ࢆ᳨ ウࡋ࡚ ࠾ࡾ ࠊ᫖ᖺ ࡢᅜ 㝿☢▼ ᢏ⾡ ఍㆟ᮦࡢᵓ㐀࡛࠶ࡿࠋᐇ㝿࡟ࡣ㔠ᒓᇶᮦࡢୖ࡟ࡣࣂࢵ

㸦MT27㸧࡛ࡣ 20K ࡛ 20T ࡢ☢ሙⓎ⏕࡟ᡂຌࡋࡓ

ࣇ࢓࣮ᒙ࡜ RE-123 ᒙࡢ㸰✀㢮࡛ࡣ࡞ࡃࠊ」ᩘࡢ

ࡇ࡜ࡀሗ࿌ࡉࢀ࡚࠸ࡿ[79]ࠋ

㓟໬≀ᒙࡸᏳᐃ໬ࡢࡓࡵࡢ Ag ᒙࡸ Cu ࡶ」ྜࡉࢀ࡚」㞧࡞ᵓ㐀ࢆ࿊ࡋ࡚࠸ࡿ[71]ࠋࡇࡢࡼ࠺࡞ RE-

5. MgB2 ⥺ᮦ

123 ࢸ࣮ࣉ⥺ᮦࡣࠊ77K ࡛㧗࠸ Jc ࡀᚓࡽࢀࡿ࡜

MgB2 ࡣ 2001 ᖺ࡟㟷ᒣᏛ㝔኱ᏛࡢỌᯇ⣧ࡽ࡟࡜ࡶ࡟ࠊᾮయ࣒࣊ࣜ࢘ ᗘ࡞࡝ࡢᴟప ୟࡘ㧗☢

ࡼࡾ Tc ࡀ 39K ࡢ㉸ఏᑟయ࡛࠶ࡿࡇ࡜ࡀぢ࠸ࡔࡉሙ࡛᭱ࡶ㧗࠸ Jc ࡀᚓࡽࢀࡿ㉸ఏᑟ⥺ᮦ࡛࠶ࡿࠋ

ࢀࡓ[80]ࠋ㖡㓟໬≀⣔࡜␗࡞ࡗ࡚㸰ඖ⣔ࡢࢩࣥࣉࣝ

᭱㏆࡛ࡣேᕤࣆࣥࡢᑟධ࡟ࡶᡂຌࡋࠊJc ࡢྥୖ࡜࡞໬Ꮫ⤌ᡂ࡛࠶ࡿࡀࠊ⤖ᬗᵓ㐀ࡣᅗ 23 ࡟♧ࡍභ␗᪉ᛶࡀⱝᖸపῶࡉࢀ࡚࠸ࡿࠋࡇࡢࡼ࠺࡞ RE-

᪉ᬗ࡛௚ࡢ㔠ᒓ㛫໬ྜ≀⣔㉸ఏᑟయ࡜ྠᵝ࡟ᒎ123 ࢸ࣮ࣉ⥺ᮦࡣ 2G conductor ࡜࿧ࡤࢀࠊᡃࡀᘏ ᛶ ࡣ ࡞ ࠸ ࠋ ᚑ ࡗ ࡚ ࠊ Nb3Sn ⥺ ᮦ ࡛ ᭱ ึ ࡟ᅜ࡛ࡣ Fujikuraࠊఫ཭㟁ᕤࠊ᫛࿴㟁⥺ࠊSuper OX

Kunzler ࡽ࡟ࡼࡾヨࡳࡽࢀࡓ PIT ἲࡀ⥺ᮦ໬ࣉ♫ࠊ⡿ᅜ࡛ࡣྂἙ㟁ᕤ㈨ᮏࡢ SuperPower ♫ࠊ⊂ࣟࢭࢫ࡜ࡋ࡚୺ὶ࡜࡞ࡗ࡚࠸ࡿࠋMgB2 ࡑࡢࡶࡢᅜ࡛ࡣ Bruker ♫ࡸ THEVA ♫ࠊ୰ᅜ࡛ࡣୖᾏ㉸ࡢ⢊ᮎࢆ㔠ᒓ⟶࡟඘ሸࡍࡿ Ex-situ ἲ[81]࡜ࠊMgఏᑟ♫ࠊ㡑ᅜ࡛ࡣ SuNAM ♫࡞࡝ࠊୡ⏺ⓗ࡟」ᩘ

Ex⢊ᮎ࡜ B ⢊ᮎࢆ඘ሸࡍࡿ In-situ ἲ[82]ࡀ࠶ࡿࠋ

ࡢ࣓࣮࣮࡛࢝㛤Ⓨࡀ⾜ࢃࢀᕷ㈍ࡶࡉࢀ࡚࠸ࡿ[75]ࠋ

situ ἲࡢሙྜࠊᙜึࡣ㔠ᒓ⟶࡟⢊ᮎࢆ඘ሸࡋࡓࡔ

Bi ⣔ࡢᵝ࡟ Ag ࢆᇶᮦ࡟౑ࢃ࡞࠸ࡇ࡜࠿ࡽᏳ౯࡛

ࡅ࡛㉸ఏᑟ㟁ὶࢆὶࡍࡇ࡜ࡀ࡛ࡁࡓࡓࡵࠊ⇕ฎ⌮࠶ࡿࡇ࡜ࡀᮇᚅࡉࢀ࡚࠸ࡿࡀࠊ࣓࣮࢟ࣟࢺࣝ⣭ࡢ୙せࡀᮇᚅࡉࢀࡓࠋࡉࡽ࡟඘ሸ⢊ᮎࡢᐦᗘࢆ㧗ࡵ㛗ᑻ࡛ᆒ୍࡞ᛶ⬟ࢆᚓࡿࡢࡣ౫↛࡜ࡋ࡚㞴ࡋࡃࠊࡿ࡯࡝ Jc ࡀྥୖࡋࠊࢩ࣮ࢫᮦ࡜ࡋ࡚◳࠸ࢫࢸࣥࡲࡓ㟁ຊᶵჾ࡞࡝ࡢ஺ὶᛂ⏝ࡸ㧗࠸☢ሙᆒ୍ᗘࣞࢫ࡞࡝ࡀ㛤Ⓨึᮇ࡟ࡣ⏝࠸ࡽࢀ࡚࠸ࡓࠋࡋ࠿ࢆᚲせ࡜ࡍࡿ㧗☢ሙ࣐ࢢࢿࢵࢺ࡟ࡣࠊᖜᗈࡢࢸ࣮

ࡋࠊࢫࢸࣥࣞࢫࡣᴟప ࡛ࡢṧ␃᢬ᢠࡀ኱ࡁࡃ⇕ࣉᙧ≧ࡢࡓࡵ࡟㉸ఏᑟᒙ࡟ㄏᑟࡉࢀࡿ㐽ⶸ㟁ὶఏᑟࡶᝏ࠸ࡓࡵࠊ᭱㏆࡛ࡣ Fe ࡸ Niࠊ࠶ࡿ࠸ࡣ Ni-࣮ࣝࣉ࡟ࡼࡿ୙ᩚ☢ሙࡢᙳ㡪ࡀၥ㢟࡜࡞ࡗ࡚࠸

Cu ྜ㔠ࡢࣔࢿࣝࡸ࢟ࣗࣉࣟࢽࢵࢣࣝ࡞࡝ࡀࢩ࣮

ࡿࠋ㐽ⶸ㟁ὶࡸ஺ὶᦆኻࡢపῶࡢࡓࡵ࡟ࢫࢡࣛ࢖

ࢫᮦ࡜ࡋ࡚౑ࢃࢀࠊࡉࡽ࡟⢏㛫ࡢ⤖ྜࢆᙉ໬ࡍࡿ

ࣅࣥࢢᢏ⾡࡟ࡼࡿ⣽ศ໬ࡀヨࡳࡽࢀ࡚࠸ࡿࡀ[76]ࠊ
ษ᩿㒊㏆ഐࡢ㉸ఏᑟ⭷ࡣࢲ࣓࣮ࢪࢆཷࡅࡸࡍࡃࠊ
ࡲࡓ㉸ఏᑟ⭷ࡀᇶᮦ࠿ࡽ๤㞳ࡋࡸࡍࡃ࡞ࡿ࡞࡝ࠊ
ࡲࡔࡲࡔㄢ㢟ࡣከ࠸ࠋ୍᪉࡛ᛂ⏝ഃ࠿ࡽࡢᮇᚅࡣ
኱ࡁࡃࠊᾮయ❅⣲୰࡛኱㟁ὶࡀ㏻㟁࡛ࡁࡿࡢ࡛ࠊ
⡿ᅜࠊࢻ࢖ࢶࠊ㡑ᅜࠊࣟࢩ࢔࡞࡝ྛᅜ࡛ࡣࠊ」ᩘ
ࡢ RE-123 ࢸ࣮ࣉ⥺ᮦࢆࡽࡏࢇ≧࡟ᕳࡁ௜ࡅࡓࢣ
࣮ࣈࣝࢆ㏦㟁ࢣ࣮ࣈࣝ࡜ࡋ࡚ᛂ⏝ࡍࡿࡇ࡜ࡀ᳨ウࡉࢀ࡚࠸ࡿ[77]ࠋࡲࡓࠊ᫖ᖺ㸦2021 ᖺ㸧࡟࣐࢖ࢡࣟࢯࣇࢺ♫࡞࡝࠿ࡽ⥲㢠࡛ 18 ൨ࢻࣝ㸦⣙ 2,040
൨෇㸧ࡢᕧ㢠࡞Ẹ㛫㈨㔠ࢆㄪ㐩ࡋ࡚ヰ㢟࡟࡞ࡗ࡚࠸ࡿࡀࠊ࣐ࢧࢳ࣮ࣗࢭࢵࢶᕤ⛉኱ᏛⓎࡢ࣋ࣥࢳࣕ
࣮࡛࠶ࡿ Commonwealth Fusion Systems ♫ࡣࠊ
SPARC ࡜࿧ࡤࢀࡿᑠᆺ᰾⼥ྜ⅔ࡢᐇ⌧࡟ྲྀࡾ⤌ࢇ࡛࠸ࡿ[78]ࠋࡇࡢ SPARC ࡣࠊࣉࣛࢬ࣐ࢆ㛢ࡌ㎸

㸲㸫 12

ᅗ 23. MgB2 ㉸ఏᑟయࡢ⤖ᬗᵓ㐀 [80]ࠋ

ᅗ 24. PVZ ♫࡛〇㐀㈍኎ࡉࢀࡿࢼࣀࢧ࢖ࢬ
ࡢ㠀ᬗ㉁ B ⢊ᮎ[83]ࠋ
ࡓࡵ࡟⇕ฎ⌮ࡀ᪋ࡉࢀ࡚࠸ࡿࠋEx-situ ἲ࡛ࡣ඘ሸࡍࡿ MgB2 ⢊ᮎࡢရ㉁ࡸࢧ࢖ࢬࡀ኱ࡁࡃᛶ⬟࡟ᙳ㡪ࡍࡿࠋ୍᪉ࠊIn-situ ἲ࡛ࡣ㔠ᒓ⟶࡟ Mg ⢊ᮎ࡜ B ⢊ᮎࢆ඘ሸࡋ࡚ఙ⥺ຍᕤࢆ⾜ࡗࡓᚋ࡟ᣑᩓ
཯ᛂࡉࡏࡿࠋ඘ሸศ⢊ᮎࡣ⣽࠿࠸࡯࡝ዲࡲࡋ࠸
ࡀࠊMg ࡣ㓟໬ࡋࡸࡍ࠸ࡓࡵ࡟ᚤ⢊ᮎࡢ〇㐀ࡣ↓⌮ࡀ࠶ࡿࠋᖹᆒ⢏ᚄࡀ 50 ࣑ࢡࣟࣥ⛬ᗘࡢ⢊ᮎࡀ୍⯡ⓗ࡟ᕷ㈍ࡉࢀ࡚࠸ࡿࠋB ⢊ᮎࡣ⤖ᬗ໬ࡋࡓ⢊ᮎࡼࡾ㠀ᬗ㉁ࡢ⢊ᮎࡢ᪉ࡀ Mg ࡜ࡢ཯ᛂᛶࡀ㧗ᅗ 25. HL-LHC ㉸ఏᑟࣜࣥࢡ࡟᥇⏝ࡉࢀࡓ(a) AGS ♫〇 Ex-situ ἲ MgB2 ⣲⥺ཬࡧ(b)ࡑࡢ㞟ྜ໬ࢣ࣮ࣈࣝ [88]ࠋ

ࡃࠊ㠀ᬗ㉁ B ࢆཎᩱ࡜ࡋ࡚౑⏝ࡍࡿሙྜࡀ୍⯡ⓗ࡛࠶ࡿࠋB ࡣࢺࣝࢥ࡛ከࡃ⏘ฟࡉࢀࠊྠᅜࡢ
Pavezyum㸦PVZ㸧♫࡛ᩘ༑ nm ࡜ࢼࣀࢧ࢖ࢬࡢ
㠀ᖖ࡟⣽࠿࠸㠀ᬗ㉁ B ⢊ᮎࡀ〇㐀࣭㈍኎ࡉࢀ࡚࠸

㸦Internal Magnesium Diffusion㸧ἲ࡜࿧ࡤࢀࡿ

ࡿ㸦ᅗ 24㸧[83]ࠋMg ⢊ᮎ࡜ B ⢊ᮎࡢ⢏ᚄࡢ᱁ᕪࡣ

〇ἲ࡛ࡢ⥺ᮦ㛤Ⓨࡶ NIMS ࡛㐍ࡵࡽࢀ࡚࠸ࡿࠋᚤ

኱ࡁࡃࠊ୧⪅ࡀᆒ㉁࡟ΰࡊࡿ࡜࠸࠺ࡼࡾࡶࠊ኱ࡁ

⣽࡞ B ⢊ᮎࡢࡳࡀࢥࣥࣃࢡࢺ࡟඘ሸࡉࢀࡓ㡿ᇦ࡞ Mg ⢊ᮎ࡟⣽࠿࠸ B ⢊ᮎࡀࡲ࡜ࢃࡾࡘࡃࡼ࠺࡞

࡟ࠊ⥺ᮦ୰ኸ࡟㓄⨨ࡉࢀࡓ Mg Წ࠿ࡽ Mg ࡀᣑᩓ≧ែ࡛࠶ࡿ࡜ᛮࢃࢀࡿࠋMgB2 ࢆ⏕ᡂࡍࡿࡓࡵࡢ

ࡍࡿࡓࡵ⦓ᐦ࡞⤌⧊ࡢ MgB2 ࡀᚓࡽࢀࡸࡍࡃࠊ཯ᛂ ᗘࡣ 650Υ⛬ᗘ࡛ಖᣢ᫬㛫ࡶ 30 ศ㹼ᩘ᫬

MgB2 ໬ྜ≀࠶ࡓࡾࡢ Jc ࡣ㧗࠸್ࡀᚓࡽࢀ࡚࠸

㛫࡜▷࠸ࠋࡉࡽ࡟ MgB2 ࡟ C㸦Ⅳ⣲㸧ࢆῧຍࡍࡿ

ࡿࠋణࡋࠊMg Წࡀ࠶ࡗࡓ⥺ᮦ୰ኸ㒊࡟ࡣࠊ⇕ฎ

࡜ࠊTc ࡣ 35K ⛬ᗘࡲ࡛పୗࡍࡿࡀࠊBc2㸦4.2 K㸧⌮ᚋ࡟኱ࡁ࡞࣎࢖ࢻࡀ࡛ࡁ࡚ࡋࡲ࠺[85]ࠋ

ࡀ 30T ㏆ࡃࡲ࡛ྥୖࡋ㧗☢ሙୗࡢ Jc ࡶྥୖࡍࡿࠋ

⌧ᅾࠊᕷ㈍ࡉࢀ࡚࠸ࡿ MgB2 ⥺ᮦࡣ PIT ἲ⥺ᮦC ῧຍࡢຠᯝࡣ SiC ῧຍࡀࡼࡃ▱ࡽࢀ࡚࠸ࡿ[84]ࠋ

ࡢࡳ࡛࠶ࡿࠋ࢖ࢱࣜ࢔ࡢ ASG ♫࠿ࡽࡣࠊEx-situ

SiC ῧຍࡢሙྜࠊ๪⏕ᡂ≀࡜ࡋ࡚ᚤ⣽࡞ Mg2Si ໬ἲ MgB2 ⥺ᮦࡀ〇㐀࣭㈍኎ࡉࢀ࡚࠸ࡿࠋ᪤࡟࣮࢜

ྜ≀ࡀ⏕ᡂࡉࢀࡿࠋࡇࡢᚤ⣽࡞ Mg2Si ࡣ MgB2 ࡢࣉࣥᆺ MRI ࡟ᛂ⏝ࡉࢀࡓᐇ⦼ࡀ࠶ࡿ[86]ࠋࡲࡓࠊ

⤖ᬗ⢏ࡢᚤ⣽໬࡟ຠᯝࡀ࠶ࡿ࡜⪃࠼ࡽࢀࡿࡀࠊ

CERN ࡢ LHC ຍ㏿ჾࡢ㧗㍤ᗘ࢔ࢵࣉࢢ࣮ࣞࢻ☢

Mg ࢆవィ࡟ᾘ㈝ࡋ࡚ࡋࡲ࠺ࠋSi ࢆྵࡲ࡞࠸ࢥࣟ

▼࡟ࣜࣥࢡࡉࡏࡿ⥲ィ 100kA ࢆ㉸࠼ࡿ㏦㟁ࢣ࣮ࢿࣥ㸦C24H12㸧ࡸ࢔ࣥࢺࣛࢭࣥ㸦C14H10㸧࡞࡝ࡢࣈࣝ࡜ࡋ࡚᥇⏝ࡉࢀࠊ2020 ᖺ࡟ 60m ࡢ 58.8kAⅣ໬Ỉ⣲ࡸࣜࣥࢦ㓟㸦C4H6O5㸧࡞࡝࡟ࡼࡿ C ῧࣉࣟࢺࢱ࢖ࣉࢣ࣮ࣈࣝࡀࢹࣔࣥࢫࢺ࣮ࣞࢩࣙࣥ

ຍ࡛ࡶ㧗☢ሙୗࡢ Jc ࡀྥୖࡍࡿຠᯝࡀㄆࡵࡽࢀ

ࡉࢀ࡚࠸ࡿࠋᅗ 25㸦a㸧ࡣ AGS ♫〇 Ex-situ ἲ࡚࠸ࡿࡀࠊ཯ᛂࡢヲ⣽ࡣ᫂ࡽ࠿࡛ࡣ࡞࠸[85]ࠋࡲࡓࠊ

MgB2 ⣲⥺ࡢ᩿㠃෗┿ࠊ㸦b㸧ࡣ㞟ྜ໬ࢣ࣮ࣈࣝࡢ

Mg ⢊ᮎࡢ௦ࢃࡾ࡟ Mg Წࢆཎᮦᩱ࡟⏝࠸ࡿ IMD᩿㠃෗┿࡛࠶ࡿ[87]ࠋ

㸲㸫 13

In-situ ἲ MgB2 ⥺ᮦࡣࠊ⡿ᅜࡢ HyperTech
Research ♫ࡀ࢜ࣁ࢖࢜ᕞ❧኱Ꮫࡢ◊✲ࢢ࣮ࣝࣉ࡜㐃ᦠࡋࠊᣢ⥆ⓗ࡟άⓎ࡞⥺ᮦ㛤Ⓨ࡟ྲྀࡾ⤌ࢇ࡛࠸ࡿࠋྠ♫࡛ࡣࠊᅗ 26 ࡟♧ࡍࡼ࠺࡞㔠ᒓࢸ࣮ࣉࢆࢳ࣮ࣗࣈ≧࡟㐃⥆ⓗ࡟ᡂᙧࡋ࡞ࡀࡽ⢊ᮎࢆ඘
ሸࡍࡿ CTFF㸦Continuous Tube Forming andFilling㸧ἲࢆ㐺⏝ࡋ࡚࠸ࡿ≉ᚩࡀ࠶ࡿ[88]ࠋᅗ 27ࡣྠ♫ࡢ MgB2 ⥺ᮦࡢ୍౛࡛࠶ࡿࡀࠊࢳ࣮ࣗࣈࣇ
࢛࣮࣑ࣥࢢᚋࡢ Nb ࣂࣜ࢔ࡣ⁐᥋ࡋ࡚࠸ࡿࡼ࠺࡛
࠶ࡿࡀ[89]ࠊࢣ࣮ࣈࣝຍᕤ࡟࠾ࡅࡿᅽ⦰࡞࡝ࢆཷࡅ
ᅗ 26. ⡿ᅜ HyperTech Research ♫ࡀ Insitu ἲ MgB2 ⥺ᮦࡢ〇㐀ࡢຍᕤἲ࡜ࡋ࡚᥇
⏝ࡋ࡚࠸ࡿ CTFF ἲ [89]ࠋ

ࡿ࡜⡆༢࡟ Nb ࣂࣜ࢔ࡢ⁐᥋㒊ࡣ◚ᦆࡋ࡚ட⿣ࡀ
⏕ࡌࡿࡓࡵࠊ඘ሸࡋࡓ Mg ⢊ᮎࡣ⇕ฎ⌮୰࡟ࣂࣜ࢔እ࡟₃ࢀ࡚ࠊCu ࡜ⴭࡋࡃ཯ᛂࡋ࡚ᛶ⬟ࡀపୗࡍࡿࡇ࡜ࡀᣦ᦬ࡉࢀ࡚࠸ࡿ[90]ࠋࡲࡓࠊHyperTech
Research ♫ࡢ⥺ᮦ࡜ࡼࡃఝࡓ᩿㠃ࡢ MgB2 ⥺ᮦࡀ㡑ᅜࡢ Sam Dong ♫࡛〇㐀࣭㈍኎ࡉࢀ࡚࠸ࡿ
㸦ᅗ 28㸧ࠋ㉸ఏᑟ≉ᛶࡶ࡯ࡰྠ➼࡛࠶ࡿ[91]ࠋణࡋࠊ
ྠ♫ࡣ୍⯡ⓗ࡞ PIT ἲ࡛ Nb ⟶ࢆཎᮦᩱ࡟⏝࠸࡚࠸ࡿࡓࡵࠊHyperTech Research ♫࡜ẚ㍑ࡍࡿ࡜
ࣂࣜ࢔ࡣ◚ᦆࡋ࡟ࡃ࠸ࠋᡃࡀᅜ࡟࠾࠸࡚ࡣࠊ⌧ẁ㝵࡛ࡣ᪥❧〇సᡤ࡛ In-situ ἲ⥺ᮦࡢ㛤Ⓨࡀ㐍ࡵࡽࢀ࡚࠾ࡾࠊCERN ࡜ KEK ࡜ࡢඹྠ㛤Ⓨ࡜ࡋ࡚ࢡࣛ࢖࢜ࢫࢺࣟࣥ⏝ࢯࣞࣀ࢖ࢻ☢▼ࡸ࣮࢜ࣉࣥ
ᆺ MRI ࡢࢥ࢖ࣝࡢヨసࡀሗ࿌ࡉࢀ࡚࠸ࡿ[92]ࠋᅗ
29 ࡣࡑࢀࡽヨస࡟⏝࠸ࡽࢀࡓ MgB2 ⥺ᮦࡢ᩿㠃

ᅗ 27. ⡿ᅜ HyperTech Research ♫〇ࡢ Insitu ἲ MgB2 ⥺ᮦࡢ᩿㠃ࡢ୍౛ࠋ࡛࠶ࡿ[93]ࠋ⥺ᮦࡢእഃ࡟ Cu-Ni ྜ㔠㸦Monel㸧ࢆ౑࠺࡜ࡇࢁࡣ HyperTech Research ♫ࡸ Sam
Dong ♫࡜㢮ఝࡋ࡚࠸ࡿࡀࠊࣂࣜ࢔ᮦࡣ Nb ࡛ࡣ࡞ࡃ Fe ࡀ⏝࠸ࡽࢀ࡚࠸ࡿࠋࡑࡢ௚࡟ࡶࠊヲࡋ࠸ෆᐜࡣ᫂ࡽ࠿࡛ࡣ࡞࠸ࡀࠊ㡑ᅜࡢ Kiswire ♫ࡸ୰ᅜࡢ WST ♫࡛ࡶ In-situ ἲ MgB2 ⥺ᮦ◊✲㛤Ⓨࡀ㐍ࡵࡽࢀ࡚࠸ࡿሗ࿌ࡀ࠶ࡿ[93, 94]ࠋ

ᅗ 28. 㡑ᅜ Sam Dong ♫〇ࡢ In-situ ἲ
MgB2 ⥺ᮦࡢ᩿㠃ࡢ୍౛ࠋᅗ 29. ᪥❧〇సᡤ〇ࡢ In-situ ἲ MgB2 ⥺ᮦࡢ᩿㠃ࡢ୍౛[93]ࠋ

㸲㸫 14

MgB2 ࡣ㓟໬≀⣔⥺ᮦ࡜␗࡞ࡗ࡚⢏⏺ࡢᙅ⤖ྜᅜ࡛ࡣ⥺ᮦ㛤Ⓨࡢᅜᐙࣉࣟࢪ࢙ࢡࢺࡶ❧ࡕୖࡆࡀ࡞࠸ࡇ࡜ࠊ㍍㔞࡛࠶ࡿࡇ࡜ࠊẚ㍑ⓗཎᮦᩱࡀᏳ

ࡽࢀࠊẚ㍑ⓗάⓎ࡟ PIT ἲ࡟ࡼࡿ⥺ᮦ㛤Ⓨࡀ㐍ࡵ౯࡛࠶ࡿࡇ࡜ࠊᚑ᮶ࡢᘬᢤࡁຍᕤ࡛୸⥺ࡢ〇㐀ࡀࡽࢀ࡚࠸ࡿ[100]ࠋణࡋࠊ㕲⣔㉸ఏᑟయࡣⓎぢࡉࢀ࡚ྍ⬟࡛࠶ࡿࡇ࡜࡞࡝」ᩘࡢ฼Ⅼࡀㄆࡵࡽࢀࡿࠋ࢝

༑ᩘᖺࡋ࠿⤒㐣ࡋ࡚࠾ࡽࡎࠊࡲࡔࡲࡔ≀㉁࡜ࡋ࡚

࣮࣎ࣥࢽ࣮ࣗࢺࣛࣝ࡞࡝ࡢᣢ⥆ྍ⬟࡞♫఍ࡢᐇᮍ▱࡞㒊ศࡀ࠶ࡿࠋຍ࠼࡚ࠊ௒ࡢ࡜ࡇࢁ Tc ࡢ㧗࠸⌧࡟ྥࡅ࡚ࠊ௒ᚋࠊᾮయỈ⣲࡜ࢱ࢖࢔ࢵࣉࡋࡓ᪂

⤌ᡂࡣ㕲࡜࡜ࡶ࡟ẘᛶࡢ࠶ࡿࣄ⣲ࢆྵࡴࡓࡵࠊୡ

ࡋ࠸ᛂ⏝࡬ࡢᒎ㛤ࡀ኱ࡁࡃᮇᚅࡉࢀࡿࠋ

⏺ⓗ࡟ぢࡿ࡜⥺ᮦ㛤Ⓨࡣᾘᴟⓗ࡛࠶ࡿࡇ࡜ࡣྰ
ࡵ࡞࠸ࠋ

6. 㕲⣔⥺ᮦ㕲⣔㉸ఏᑟయࡣ 2008 ᖺ࡟ᮾிᕤᴗ኱Ꮫࡢ⣽㔝⚽㞝ࡽࡢ◊✲ࢢ࣮ࣝࣉࡼࡾⓎぢࡉࢀࡓ[95]ࠋᅗ 30࡟♧ࡍࡼ࠺࡞㉸ఏᑟࢆᢸ࠺ FeAs 㠃ࡀ⤯⦕ᒙ࡛ᣳࡲࢀࡓᒙ≧ࡢ⤖ᬗᵓ㐀ࢆᣢࡕ[96]ࠊࡇࡢⅬࡣ㖡㓟໬≀⣔㉸ఏᑟయ࡜㢮ఝࡋ࡚࠸ࡿࠋ㕲⣔࡛㉸ఏᑟࢆ♧ࡍ⤖ᬗᵓ㐀⩌࡟ࡣࠊ1111 ᆺ㸦LaFeAsO1-xFx ࡸ
SmFeAsO1-xFx ࡞࡝㸧ࠊ111 ᆺ㸦LiFeAs ࡞࡝㸧ࠊ11ᆺ㸦FeSe ࡸ FeTe ࡞࡝㸧ࠊ122 ᆺ㸦BaFe2As2 ࡞࡝㸧ࡢ 4 ✀㢮ࡀሗ࿌ࡉࢀ࡚࠸ࡿ[97]ࠋ☢ᛶࢆ♧ࡍඖ⣲ࢆྵࢇࡔ≀㉁ࡀẚ㍑ⓗ㧗࠸ Tc ࢆ♧ࡍࡓࡵࠊᇶ♏⌮ㄽࡸ≀ᛶ≀⌮ࡢศ㔝࠿ࡽᙉ࠸⯆࿡ࢆ㞟ࡵࡓࠋ㔠ᒓ⣔࡜ྠࡌࡃࢡ࣮ࣃ࣮ᑐࡢᑐ⛠ᛶࡀ s Ἴ࡛࠶ࡿࡓࡵd Ἴ࡛࠶ࡿ㖡㓟໬≀⣔࡯࡝⤖ᬗ㓄ྥ࡟ᩄឤ࡛࡞࠸
ࡇ࡜ࡸࠊᴟప ࡛ࡢ Bc2 ࡀ 50T ௨ୖ࡜ A15 ᆺ໬ྜ≀⣔ࡼࡾ᱁ẁ࡟㧗࠸≉ᚩࡀ࠶ࡿࠋཎᩱࡀẚ㍑ⓗᏳ౯࡛࠶ࡿࡇ࡜ࡶᐇ⏝⥺ᮦೃ⿵࡜ࡋ࡚᭷฼࡜ᮇ
ᚅࡉࢀࠊ⥺ᮦ໬ࡢྲྀࡾ⤌ࡳࡣᡃࡀᅜ࡟࠾࠸࡚ࡶ࠸
ࡃࡘ࠿ࣛ࣎ࢫࢣ࣮ࣝࡢሗ࿌ࡀ࠶ࡿ[98, 99]ࠋ㞄ᅜࡢ୰

ᅗ 30. 㕲ࢆྵࡴ᪂ᆺ㉸ఏᑟయ LaFeAsO1-xFx
㸦1111 ᆺ㸧ࡢ⤖ᬗᵓ㐀[96]ࠋཧ ⪃ ᩥ ⊩
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