高性能磁気熱変換材料の開発を目指して

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Title

高性能磁気熱変換材料の開発を目指して

Author(s)

戎, 修二; 阿波加, 淳司; 藤, 耕一郎

Citation

室蘭工業大学紀要 Vol.63, pp.33-36, 2014

Issue Date

2014-03-18

URL

http://hdl.handle.net/10258/2827

Rights

－　33　－ ᐊᕤ኱⣖せ➨63 ྕ㸦2013㸧 33㹼36

- 33 -

㧗ᛶ⬟☢Ẽ⇕ኚ᥮ᮦᩱࡢ㛤Ⓨࢆ┠ᣦࡋ࡚

ᡁ

ಟ஧

*1, *2

_㸪㜿Ἴຍ

_῟ྖ

*2

_㸪⸨

_⪔୍㑻

*3

Aiming for High Performance Magnetocaloric Materials

Shuji EBISU

*1, *2

_{, Junji AWAKA}

*2

_{, and Koichiro FUJI}

*3

㸦ཎ✏ཷ௜᪥ ᖹᡂ

25 ᖺ 9 ᭶ 30 ᪥ ㄽᩥཷ⌮᪥ ᖹᡂ 26 ᖺ 1 ᭶ 24 ᪥㸧

Abstract

Specific heat measurements on single crystals of rare-earth sesquisulfide α-R2S3 (R = Pr, Nd, Sm, Gd,

Tb and Dy) have been performed under applied magnetic fields in the range between 0 and 5 T. Any compound shows one or two peak(s) at magnetic transition temperature(s) in the temperature dependence of the specific heat. The values of the specific heat below the temperature of 10 K for

α-Gd2S3 are considerably larger than those for other α-R2S3 and comparable to those for other cold

storage materials. Application of magnetic field perpendicular to the b-axis of α-Dy2S3 single crystal

shifts the antiferromagnetic transition temperature TN1 toward higher temperature and decreases

magnetic entropy. In this case, adiabatic demagnetization after isothermal magnetization at 12 K with a magnetic field of 5 T yields a magnetic refrigeration effect of Tad= 5.8 K.

Keywords : Rare-earth sesquisulfide, Magnetocaloric effect, Magnetic refrigeration, Cold storage material, Specific heat

1 ࡣࡌࡵ࡟ ᐊ⹒ᕤᴗ኱Ꮫ➨㸰ᮇ୰ᮇ┠ᶆᮇ㛫࡟࠾ࡅࡿ㔜Ⅼ ◊✲ࣉࣟࢪ࢙ࢡࢺ㸸ࠕᕼᅵ㢮࡟㛵㐃ࡋࡓ෌⏕ྍ⬟࢚ ࢿࣝࢠ࣮ᮦᩱ⛉Ꮫ࠾ࡼࡧࢧࢫࢸ࢕ࢼࣈࣝᮦᩱ㛤 Ⓨࠖ䠄␎⛠㸸ᕼᅵ㢮ࣉࣟࢪ࢙ࢡࢺ䠅ࡀᖹᡂ_{22 ᖺ࡟Ⓨ} ㊊ࡋࠊᙜึ❧ࡕୖࡀࡗࡓ㸱ࢱࢫࢡ◊✲ࡢ࠺ࡕࡢ㸯 ࡘࡀࠊ䛂㧗ᛶ⬟☢Ẽ⇕ኚ᥮ᮦᩱࡢ㛤Ⓨ䛃ࢱࢫࢡ࡛࠶ ࡿࠋ ࡼࡃ▱ࡽࢀࡿ☢ᛶᮦᩱࡢᛂ⏝ࡣࠊ☢ሙ࡟ࡼࡿᛂ ⟅࡛࠶ࡿ☢໬ࢆ฼⏝ࡍࡿࡶࡢࡸࠊ㟁Ẽ࡜☢Ẽࡢ┦ ஫స⏝ࢆ฼⏝ࡍࡿࡶࡢࡀ኱༙࡛࠶ࡿࠋ୍᪉࡛ࠊእ 㒊☢ሙࡣ☢ᛶయෆ㒊ࡢ☢Ẽ࣮࣓ࣔࣥࢺ࡟స⏝ࡋࠊ ☢Ẽ࢚ࣥࢺࣟࣆ࣮ኚ໬ࢆ௓ࡋ࡚⇕ࡢ⛣ື࡜ࡶ㛵㐃 ࡍࡿࠋࡇࡢࡼ࠺࡟☢Ẽ࡜⇕㔞ࡀ⤖ྜࡍࡿ⌧㇟ࢆ☢ Ẽ⇕㔞ຠᯝ䠄_{MCE; Magnetocaloric Effect䠅࡜࠸࠺ࠋ}  *1 ᐊ⹒ᕤᴗ኱Ꮫ ࡋࡃࡳ᝟ሗ⣔㡿ᇦ  *2 ᐊ⹒ᕤᴗ኱Ꮫ ⎔ቃㄪ࿴ᮦᩱᕤᏛ◊✲ࢭࣥࢱ࣮  *3 ᐊ⹒ᕤᴗ኱Ꮫ ᛂ⏝⌮໬Ꮫ⣔ᑓᨷ ☢ሙࡣ☢໬࡜࢚ࢿࣝࢠ࣮ⓗ࡟ඹᙺࡢ㛵ಀ࡟࠶ࡾࠊ ࡇࢀࡣ⇕ຊᏛⓗ࡟Ẽయࡢᅽຊ࣭య✚ࡢ㛵ಀ࡜ྠ➼ ࡛࠶ࡿࠋࡋࡓࡀࡗ࡚ࠊ୍⯡ࡢ෭෾ᶵࡀẼయࡢᅽ⦰࣭ ⭾ᙇ࡟ࡼࡾ෭༷ຠᯝࢆᚓࡿࡢ࡟ᑐᛂࡋ࡚ࠊ࠶ࡿ✀ ࡢ☢ᛶయ࡟☢ሙࢆບ☢࣭ᾘ☢ࡍࡿࡇ࡜࡟ࡼࡾ෭༷ ࡍࡿࡇ࡜ࡀྍ⬟࡛࠶ࡾࠊࡇࢀࢆ☢Ẽ෭෾䠄Magnetic Refrigeration䠅࡜࠸࠺ࠋࡲࡓࠊMCE ࡟ࡼࡾ୍⯡ⓗ ࡟☢ᛶయࡣ☢Ẽ┦㌿⛣Ⅼ䠄 ᗘ䠅࡟࠾࠸࡚ẚ⇕ࡀඛ 㗦࡞ᴟ኱ࢆ♧ࡍࡢ࡛ࠊ☢Ẽ┦㌿⛣Ⅼࢆ㊬ࡄ ᗘୖ ᪼ࢆࡶࡓࡽࡍࡓࡵ࡟ࡣ㠀ᖖ࡟኱ࡁ࡞⇕㔞ࡀᚲせ࡜ ࡞ࡿࠋࡇࡢຠᯝࡀ኱ࡁ࠸≀㉁ࡣ䇾෭䇿ࢆ⵳࠼ࡿ⵳෭ ᮦ࡜ࡋ࡚฼⏝࡛ࡁࠊ෭෾ᶵ࡟඘ሸࡍࡿ➼ࡋ࡚෭༷ ຠ⋡ࢆྥୖࡉࡏࡿࡇ࡜ࡀ࡛ࡁࡿࠋᮏࢱࢫࢡ◊✲࡛ ࡣ☢Ẽ෭෾ᮦࡸ⵳෭ᮦࡢ㛤Ⓨࢆᣦྥࡋ࡚࠸ࡿࠋ 2 ⫼ᬒ࡜◊✲ᣦ㔪  ⵳෭ᮦ࡜ࡋ࡚ࡣࠊ☢Ẽ㌿⛣➼ࡢ┦㌿⛣࡟కࡗ࡚ ኱ࡁ࡞ẚ⇕ࣆ࣮ࢡࢆ⏕ࡌࡿࡶࡢࡀ㐺ࡋ࡚࠾ࡾࠊ኱ 室工大紀要第_{63 号（2013） 33~36}

_{特　　　集}

－　34　－ 㧗ᛶ⬟☢Ẽ⇕ኚ᥮ᮦᩱࡢ㛤Ⓨࢆ┠ᣦࡋ࡚

- 35 -

ࡿ࡜㢮᥎ࡉࢀࡿࠋ୍᪉࡛୰ᛶᏊᅇᢡᐇ㦂(20)_ࡸ࢚ࣥ ࢺࣟࣆ࣮ኚ໬(21)_{࠿ࡽ☜ㄆࡉࢀࡿࡼ࠺࡟ࠊα-Gd2S3ࡣ} 㸯ẁࡢ㌿⛣࡛_{Gd1, Gd2 ࡀ཯ᙉ☢ᛶ⛛ᗎ໬ࡍࡿࠋ} 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0 5 10 15 20

C

/ J

K

-1

c

m

-3

T / K

-

R

2

S

3 R = Gd Tb Dy Pr Nd Sm ᅗ_{1 α-R2S3}༢⤖ᬗࡢẚ⇕ࡢ ᗘ౫Ꮡᛶ  ᅗ_{1 ࠿ࡽ᫂ࡽ࠿࡞ࡼ࠺࡟ࠊα-Gd2S3}ࡢẚ⇕ࣆ࣮ࢡ ࡣ௚ࢆᅽಽࡋ࡚኱ࡁ࠸ࠋከ㔜㡯ᇶᗏ≧ែ࡟࠾࠸࡚ Gd3+_{ࡢ඲ゅ㐠ື㔞J ࡣ 7/2 ࡜ẚ㍑ⓗ኱ࡁ࠸ࡀࠊTb}3+ (J = 6)ࡸ Dy3+ _{(J = 15/2)ࡢ᪉ࡀࡉࡽ࡟኱ࡁ࠸ࠋࡋ࠿ࡋࠊ} Gd ⣔௨እࡢ J ከ㔜㡯ࡣ⤖ᬗሙ࡟ࡼࡗ࡚࢚ࢿࣝࢠ࣮ ‽఩ศ⿣ࡋࠊᇶᗏ㡯ࡢከ㔜ᗘࡣపࡃ࡞ࡿࠋ୍᪉Gd ⣔࡛ࡣ㌶㐨ゅ㐠ື㔞ࡀ _{0 ࡛࠶ࡿࡓࡵ࡟⤖ᬗሙࡢᙳ} 㡪ࢆཷࡅࡎࠊᇶᗏࡀࢫࣆࣥ 8 㔜㡯࡛࠶ࡿࡇ࡜࡟㉳ ᅉࡋ࡚ẚ⇕ࣆ࣮ࢡࡀ኱ࡁࡃ࡞ࡗ࡚࠸ࡿࠋࡉࡽ࡟_Gd ⣔࡛ࡣ㌿⛣ࡼࡾప ࡛ẚ⇕ࡀ⫪ࢆࡶࡗ࡚࠸ࡿࠋࡇ ࢀࡣᗄఱᏛⓗࣇࣛࢫࢺ࣮ࣞࢩࣙࣥࢆ᭷ࡍࡿ_{Gd2 ࡢ} ⛛ᗎ໬ࡀGd1 ࡢ⮬Ⓨ⛛ᗎ࡟ࡼࡿศᏊሙࡢᙳ㡪࡛ࠊ  ᗘపୗ࡟కࡗ࡚ᚎࠎ࡟㐍⾜ࡋ࡚࠸ࡿࡇ࡜࡟㉳ᅉ ࡋ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿ(21)ࠋࡇࡢࡓࡵࠊα-Gd2S3ࡣᗈ ࠸ ᗘ⠊ᅖ࡛኱ࡁ࡞ẚ⇕ࢆࡶࡘࠋ༢఩య✚࠶ࡓࡾ ࡢẚ⇕ࡢ᭱኱್0.63 J K-1cm-3 (T = 9.8 K)ࡣ⵳෭ᮦ ࡜ ࡋ ࡚ ᮇ ᚅ ࡉ ࢀ ࡚ ࠸ ࡿ _{Gd2O2S (GOS) ࡢ 1.1} J K-1_cm-3 _{(T = 5.2 K)ࡼࡾࡶప࠸ࡀࠊᐇ⏝໬ࡉࢀ࡚࠸} ࡿ_{Er3Ni ࡸ HoCu2}ࢆ෽㥙ࡋ࡚࠸ࡿࠋ_HoCu2ࡀࢲࣈࣝ ࣆ࣮ࢡ࡛ࡼ࠸ᛶ⬟ࢆ♧ࡍ ᗘᇦ࡛ࡣ್ࡀୗᅇࡿࡀ α-Gd2S3ࡢᖜᗈࡢ⫪ࡣⰋ࠸≉ᚩ࡛࠶ࡿࠋࡲࡓࠊࡼࡾ ኱ࡁ࡞ẚ⇕ࣆ࣮ࢡࢆࡶࡘᙉ☢ᛶయ _{ErNi ࡛ࡣ࡞ࡃ} Er3Ni ࡀᐇ⏝໬ࡉࢀ࡚࠸ࡿ⌮⏤ࡣᚋ⪅ࡀ཯ᙉ☢ᛶయ ࡛࠶ࡾ㉸ఏᑟ࣐ࢢࢿࢵࢺ࠿ࡽࡢ₃ࢀ☢ሙࡢᙳ㡪ࢆ ཷࡅ࡟ࡃ࠸ࡓࡵ࡛࠶ࡿࡀࠊࡑࡢⅬ࡛ࡶ཯ᙉ☢ᛶయ α-Gd2S3ࡣ㐺ࡋ࡚࠸ࡿࠋ኱ࡁ࡞ẚ⇕ࢆ♧ࡍ ᗘᇦࡀ ␗࡞ࡿ⵳෭ᮦࢆ⤌ࡳྜࢃࡏ࡚෭෾ᶵ➼࡟඘ሸࡍࡿ ࡇ࡜࡟ࡼࡾ㧗ຠ⋡໬ࡀᅗࢀࡿࡓࡵࠊࢲࣈࣝࣆ࣮ࢡ ࢆ♧ࡍ௚ࡢ _α-R2S3ࡶྵࡵࠊẚ⇕≉ᛶⓗ࡟ࡣ⵳෭ᮦ ࡜ࡋ࡚ࡢྍ⬟ᛶࡣ࠶ࡿࠋࡋ࠿ࡋᐇᮦᩱ࡜ࡋ࡚ࡣࠊ ⌫≧ከ⤖ᬗヨᩱࡢసᡂྍ⬟ᛶࠊࡑࡢሙྜࡢẚ⇕≉ ᛶࡸ⇕ఏᑟ⋡ࠊ⇕ࢧ࢖ࢡࣝࢆྵࡵࡓ⪏⎔ቃᛶࠊࢥ ࢫࢺ➼ࡢ᳨ウࡍ࡭ࡁㄢ㢟ࡣᩘከࡃᏑᅾࡍࡿࠋ 4.2 ☢ሙ୰ẚ⇕  ᅗ_{2 ࡟ α-Dy2S3}ࡢ_{b ㍈࡟ᑐࡋ࡚ᆶ┤࡟☢ሙࢆ༳ຍ} ࡋࡓሙྜࡢ_{(a)☢Ẽẚ⇕ C}m࠾ࡼࡧ(b)☢Ẽ࢚ࣥࢺࣟ ࣆ࣮_Smࡢ ᗘ౫Ꮡᛶࢆ♧ࡍࠋ㧗 ഃ㌿⛣Ⅼ_TN1ࡀ☢ ሙ༳ຍ࡟ࡼࡾ㢧ⴭ࡟㧗 ഃ࡟ࢩࣇࢺࡋࠊప ഃ㌿ ⛣ࡀᾘኻࡋ࡚࠸ࡿᵝᏊࡀࢃ࠿ࡿࠋᙉ☢ᛶ㌿⛣ࡀ☢ ሙ༳ຍ࡟ࡼࡾ㧗 ഃ࡟ࢩࣇࢺࡍࡿࡇ࡜ࡣࡼࡃぢࡽ ࢀࡿࡇ࡜࡛ࠊࡇࡢഴྥࡣ☢Ẽ෭෾࡟࡜ࡗ࡚ࡣ㒔ྜ ࡀⰋ࠸ࠋࡋ࠿ࡋࠊ཯ᙉ☢ᛶ㌿⛣ࡣ☢ሙ༳ຍ࡟ࡼࡾ ప ഃ࡟ࢩࣇࢺࡍࡿࡢࡀ୍⯡ⓗ࡛࠶ࡿࠋ⌧࡟௚ࡢ α-R2S3࡛ࡣ☢ሙࡢ༳ຍ᪉ྥ࡟ࡼࡽࡎ㌿⛣ࡢప ࢩ ࣇࢺࡀほ ࡉࢀࡿࡋࠊ_α-Dy2S3ࡢ_{b ㍈࡟ᖹ⾜࡞☢ሙ} ༳ຍ࡛ࡶྠᵝࡢഴྥࡀぢࡽࢀࡿࠋα-Dy2S3ࡣ㏲ḟ཯ ᙉ☢ᛶ㌿⛣Ⅼࡢ㛫_TN1-TN2࡛✀ࠎࡢ≉␗࡞⌧㇟ࢆ♧ ࡍ(13)(14)_{ࡀࠊb ㍈࡟ᆶ┤࡞☢ሙ࡟ᑐࡍࡿᛂ⟅ࡀ㗦ᩄ} ࡛࠶ࡿࡇ࡜ࡶࡑࡢ୍ࡘ࡛࠶ࡿࠋ_{Dy1 ࡀ཯ᙉ☢ᛶ⛛} ᗎ໬ࡍࡿࡇ࡜࡟ࡼࡾࠊ_{Dy2 ࡢ☢ሙ࡟ᑐࡍࡿᛂ⟅ᛶ} ࡀࡼࡃ࡞ࡾࠊ☢ሙ࡟ࡼࡿࢮ࣮࣐࢚ࣥࢿࣝࢠ࣮పୗ ࡀ࠶ࡿࡓࡵ࡟ࠊTN1ࡀ㧗 ࢩࣇࢺࡍࡿ࡜⪃࠼ࡽࢀࡿࠋ 0 10 20 30 40 50

-

Dy

₂

S

₃

C

m

/ J

K

-1

mol

-1

Hԋb

0 T 1 T2 T 3 T 5 T

(a)

0 5 10 15 20 0 5 10 15 20

-

Dy

₂

S

₃

S

m

/ J

K

-1

mol

-1

Hԋb

0 T1 T 2 T 5 T 3 T

(b)

T / K

ᅗ2 α-R2S3༢⤖ᬗࡢ☢ሙ୰࡛ࡢ(a)☢Ẽẚ⇕࡜ (b)☢Ẽ࢚ࣥࢺࣟࣆ࣮ࡢ ᗘ౫Ꮡᛶ  _TN1ࡢ㧗 ࢩࣇࢺ࡜ప ഃ_TN2࡛ࡢ㌿⛣ࡢᾘኻࡀ ࡜ࡶ࡟ຠ࠸࡚ࠊᅗ2(b)࡟♧ࡍࡼ࠺࡟ Cm/T ࢆ ᐃ᭱ ప ᗘ _{0.4 K ࠿ࡽ ᗘ࡛✚ศࡋࡓ☢Ẽ࢚ࣥࢺࣟࣆ} ࣮ࡣ☢ሙ༳ຍ࡟ࡼࡾῶᑡࡋ࡚࠸ࡿ㸦|Sm| < 0㸧ࠋບ ☢࡟Ọஂ☢▼ࡢ฼⏝ࢆ᝿ᐃࡋࡓ☢ሙ _{2 T ࡛ࡢ|Sm|} ᡁ ಟ஧㸪㜿Ἴຍ ῟஧㸪⸨ ⪔୍㑻

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ࡁ࡞඲ゅ㐠ື㔞㔞Ꮚᩘࢆࡶࡘ㔜ᕼᅵ㢮ඖ⣲ࢆྵࡴ ≀㉁ࡀೃ⿵࡜࡞ࡾᚓࡿࠋ_{10 K ⛬ᗘ࡛☢Ẽ┦㌿⛣ࢆ} ࡶࡘ_{α ኚែᕼᅵ㢮୕஧◲໬≀ α-R2S3}䠄_{R㸸ᕼᅵ㢮ඖ} ⣲䠅ࡸᕼᅵ㢮࣍࢘໬≀࡟╔┠ࡋࠊ⣔⤫ⓗ࡞ẚ⇕ ᐃ ࢆ⾜ࡗࡓࠋ  ☢Ẽ෭෾ᮦ࡟㛵ࡋ࡚ࡣືస ᗘࢆ⪃៖ࡍࡿࡇ࡜ ࡀ㔜せ࡛࠶ࡾࠊᮏࢱࢫࢡ࣓ࣥࣂ࣮ࡀࡶࡘࢩ࣮ࢬࢆ ㋃ࡲ࠼ࠊ_{(1)ᐊ ᇦࠊ(2)ᾮయ❅⣲ ᗘᇦࠊ(3)10 K} ᗘᇦ࡛ࡢ᳨ウࢆ⾜ࡗࡓࠋ  _{(1)ᐊ ᇦ㸸ᐊ ᇦ࡟࠾ࡅࡿ☢Ẽ෭෾ᶵࡣࠊࣇࣟ} ࣥ࢞ࢫ࡟ࡼࡿ࢜ࢰࣥᒙࡢ◚ቯࠊ௦᭰ࣇࣟࣥ࢞ࢫ࡟ ࡼࡿᆅ⌫ ᬮ໬ࡢಁ㐍ࢆ㜼ࡴࡶࡢ࡜ࡋ࡚ᮇᚅࡉࢀ ࡚࠸ࡿࠋࡇࡢ ᗘᇦ࡟࠾࠸࡚ࡣࠊᐊ ௜㏆࡟ᙉ☢ ᛶ㌿⛣ ᗘ䠄࣮࢟ࣗࣜⅬ䠅TC ࢆࡶࡘᕼᅵ㢮ඖ⣲ Gd ࡀึᮇࡢ㡭ࡼࡾὀ┠ࡉࢀ࡚ᐇᶵ࡛ࡶホ౯ࡉࢀࠊᐊ  ☢Ẽ෭෾ࢩࢫࢸ࣒ࡢⓎᒎ࡟኱ࡁ࡞ᙺ๭ࢆᢸࡗ࡚ ࡁࡓࠋ㧗ຠ⋡࣭㧗ᛶ⬟໬ࡢࡓࡵ࡟✀ࠎࡢ_{Gd ໬ྜ≀ࠊ} ౛࠼ࡤ_Gd5Si2Ge2(1)(2)ࡸࠊ㠀☢ᛶࡢᕼᅵ㢮ඖ⣲La ࢆ ྵࡴ _{La(Fe1-xSix)13Hy}(3)(4)_{࠶ࡿ࠸ࡣᕼᅵ㢮ඖ⣲ࢆྵࡲ} ࡞࠸_Mn(As1-xSbx)(5)ࡸ MnFe(P1-xAsx)(6)࡞࡝ࡀὀ┠ࢆ 㞟ࡵ࡚┒ࢇ࡟◊✲ࡉࢀࠊᐇ⏝໬࡟㏆࡙࠸࡚࠸ࡿࠋ ᕼᅵ㢮ඖ⣲ࢆ⏝࠸ࡎ࡜ࡶࠊ୍ḟ┦㌿⛣ࡢ኱ࡁ࡞࢚ ࣥࢺࣟࣆ࣮ኚ໬ࢆ฼⏝ࡍࢀࡤ㧗ᛶ⬟ࡢ෭෾ᶵࢆᐇ ⌧࡛ࡁࡿྍ⬟ᛶࡀ♧ࡉࢀࠊ⌧ᅾࡢ୍ࡘࡢ₻ὶ࡜࡞ ࡾࡘࡘ࠶ࡿࠋᚋⓎࡢᮏࢱࢫࢡ࡛ࡣࠊ⌧᭷ࡢࢩ࣮ࢬ ࡛࠶ࡿᐊ ᇦ࡛␗ᖖ࡟኱ࡁ࡞⇕⭾ᙇ⋡䠄ẚ⇕࡜ᐦ ᥋࡟㛵㐃ࡍࡿ≀⌮㔞䠅ࢆ♧ࡍᕼᅵ㢮ඖ⣲ _{Ce ࢆྵࡴ} ᵓ㐀୙つ๎⣔ྜ㔠(7)-(9)_{ࡢᇶ♏◊✲ࢆ㐍ࡵࡓࠋ}  _{(2)ᾮయ❅⣲ ᗘᇦ㸸㖡㓟໬≀㧗 ㉸ఏᑟయࢆ⏝} ࠸ࡓ✀ࠎࡢࢹࣂ࢖ࢫࡀ฼⏝ࡉࢀ࡚ࡁ࡚࠸ࡿࡀࠊࡇ ࡢᏳ ᐃືసࡢ ࡓࡵ࡟ࡣ ᾮయ❅ ⣲ ᗘ 䠄❅⣲ࡢ Ἓ Ⅼ㸸_{77 K䠅ࡼࡾᩘ༑ K ప࠸ ᗘࡀᚲせ࡛࠶ࡾࠊࡇࢀ} ࢆᐇ⌧ࡍࡿపࢥࢫࢺ࣭ప᣺ື࣭ప㦁㡢ࡢᑠᆺ☢Ẽ ෭෾ᶵࡀᮃࡲࢀࡿࠋࡑࡢᙧᡂࣃࢱ࣮ࣥ࠿ࡽࢫࢺࣛ ࢖ࣉ⛛ᗎ࡜࿧ࡤࢀࡿ㟁Ⲵ⛛ᗎࢆ㉸ఏᑟ㌿⛣࡟కࡗ ࡚㉳ࡇࡍ㖡㓟໬≀㧗 ㉸ఏᑟయ࡟㛵ࡍࡿ◊✲ࢩ࣮ ࢬ(10)_{ࡀ࠶ࡾࠊࡇࡢ㌿⛣࡟క࠺࢚ࣥࢺࣟࣆ࣮ኚ໬ࢆ} ྵࡵࡓᇶ♏◊✲࡟ྲྀࡾ⤌ࢇࡔࠋ  _{(3)10 K  ᗘᇦ㸸ࢡ࣮࢚ࣜࣥࢿࣝࢠ࣮࡜ࡋ࡚ᮇᚅ} ࡉࢀࡿỈ⣲⇞ᩱࢆ㈓ⶶ࣭㍺㏦ࡍࡿࡓࡵ࡟ࡣỈ⣲ࢆ ᾮ໬ࡍࡿࡢࡀຠ⋡ⓗ࡛࠶ࡾࠊ_{10 K ⛬ᗘࡢ ᗘࢆᐇ} ⌧ࡍࡿᚲせࡀ࠶ࡿࠋᾮయ࣒࣊ࣜ࢘ࢆ౑⏝ࡍࢀࡤࠊ ᾐₕࡍࡿࡔࡅ࡛࣒࣊ࣜ࢘ࡢἛⅬ _{4.2 K ㏆ࡃࡲ࡛෭} ༷ࡍࡿࡇ࡜ࡀྍ⬟࡛࠶ࡿࡀࠊ࣒࣊ࣜ࢘ࡣᕼᑡ㈨※ ࡛࠶ࡾࠊ♫఍᝟ໃ࡟ࡼࡗ࡚ࡣ☜ಖࡀࡁࢃࡵ࡚ᅔ㞴 ࡟ࡶ࡞ࡾᚓࡿࠋࡇࡢࡓࡵࠊ࣒࣊ࣜ࢘ࣇ࣮࡛ࣜྠ➼ ࡢ ᗘࢆᚓࡿᑠᆺ࣭పࢥࢫࢺ࣭ప᣺ື࣭ప㦁㡢ࡢ ☢Ẽ෭෾ᶵࡢ㛤Ⓨࡀᮇᚅࡉࢀ࡚࠸ࡿࠋࡇࢀࡲ࡛ⴭ ⪅ࡣ๓㏙ࡢ_α-R2S3ࡀ_{10 K ௜㏆ࡢ ᗘ࡛㏲ḟ☢Ẽ┦} ㌿⛣ࢆ㉳ࡇࡋࠊࡑࢀ࡟కࡗ࡚✀ࠎࡢ≉␗࡞≀ᛶᛂ ⟅ࢆ♧ࡍࡇ࡜ࢆぢฟࡋ࡚ࡁࡓ(11)-(18)_{ࠋࡇࡢ◊✲ࢩ࣮} ࢬࢆά࠿ࡋࠊα-R2S3ࡢ☢Ẽ෭෾ᮦ࡜ࡋ࡚ࡢྍ⬟ᛶࢆ ᥈ࡗࡓࠋ  α-R2S3ࡣᩳ᪉ᬗ⣔⤖ᬗᵓ㐀䠄✵㛫⩌㸸Pnma䠅୰࡟ ⤖ᬗᏛⓗ࡟⊂❧࡞஧ࡘࡢᕼᅵ㢮ࢧ࢖ࢺ㸦_{R1, R2㸧ࢆ} ᭷ࡋ࡚࠸ࡿ(11)_{ࠋࡇࢀࡲ࡛࡟ᚓࡽࢀࡓᐇ㦂஦ᐇࢆ⥲} ᣓࡍࡿ࡜ࠊ_{R1 ࡣ b ㍈᪉ྥ୍ḟඖ㙐ෆ࡛ᙉ☢ᛶⓗࠊa} ㍈᪉ྥࢪࢢࢨࢢ㙐ෆ࡛཯ᙉ☢ᛶⓗ࡟⛛ᗎ໬ࡍࡿഴ ྥࡀᙉࡃࠊ_{R1 ࡜ᙅࡃ⤖ྜࡋࡓ R2 ࡣ㊥㞳ⓗ࡟ࡣࡸ} ࡸ㐲࠸㞄᥋ R2 ࡜」㞧࡟స⏝ࡋྜ࠺࡜⪃ᐹࡉࢀࡿࠋ ࡇࡢ_{R1-R2, R2-R2 㛫ࡢ」㞧࡞☢Ẽⓗ┦஫స⏝ࡀ➇} ྜࡋࠊ ᗘࡸ☢ሙ࡟ᑐࡋ࡚࣐ࢡࣟ≀ᛶࡀ≉␗࡞ᛂ ⟅ࢆ♧ࡍ࡜⪃࠼ࡽࢀࡿࠋᮏሗ࿌࡛ࡣࠊ_α-R2S3ࡢ↓☢ ሙୗ࠾ࡼࡧ☢ሙ୰࡛ࡢẚ⇕ࡢ ᐃ⤖ᯝ࡜⵳෭ᮦ࣭ ☢Ẽ෭෾ᮦ࡜ࡋ࡚ࡢྍ⬟ᛶ࡟ࡘ࠸࡚㆟ㄽࡍࡿࠋ 3 ᐇ㦂  ᕷ㈍ࡢᕼᅵ㢮㓟໬≀ࢆ _CS2Ẽὶ୰࡛ຍ⇕ࡍࡿࡇ ࡜࡛ α-R2S3⢊ᮎヨᩱࢆᚓࠊࡇࢀࢆཎᩱ࡜ࡋ࡚ࣚ࢘ ⣲ࢆ㍺㏦๣࡜ࡋࡓẼ┦໬Ꮫ㍺㏦ἲ࡟ࡼࡾ༢⤖ᬗヨ ᩱࢆ⫱ᡂࡋࡓࠋẚ⇕ࡣ⡿ᅜQuantum Design ♫〇≀ ⌮≉ᛶ ᐃࢩࢫࢸ࣒ _{PPMS ࢆ౑⏝ࡋࠊ5 T ࡲ࡛ࡢ} ✀ࠎࡢ☢ሙ୰࡛⦆࿴ἲ࡟ࡼࡾ ᐃࡋࡓࠋ 4 ⤖ᯝ࡜⪃ᐹ 4.1 ↓☢ሙୗẚ⇕  ᅗ_{1 ࡟ α-R}2S3䠄R㸸Pr, Nd, Sm, Gd, Tb, Dy䠅༢⤖ᬗ ࡢ↓☢ሙୗ࡛ࡢẚ⇕ࡢ ᗘ౫Ꮡᛶࢆ♧ࡍࠋ_{Gd, Pr} ⣔௨እࡢ α-R2S3࡛ࡣ㸰ẁࡢ☢Ẽ┦㌿⛣࡟క࠺ඛ㗦 ࡞ࣆ࣮ࢡࡀ☜ㄆࡉࢀࡿࠋ_{Tb, Dy ⣔࡟㛵ࡋ࡚ࡣ☢໬}  ᐃ(12)(14)_{ࡸ୰ᛶᏊᅇᢡᐇ㦂}(19)_{ࡢ⤖ᯝ࠿ࡽࠊ㸰ẁࡢ} ཯ᙉ☢ᛶ㌿⛣ࡀ㉳ࡁ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿࠋ_{Nd ⣔ࡢ} ᑡ࡞ࡃ࡜ࡶ㧗 ഃࣆ࣮ࢡࡣࡸࡣࡾ཯ᙉ☢ᛶ㌿⛣࡟ ࡼࡿࡶࡢ࡛࠶ࡿࠋࡇࢀ࡟ᑐࡋ࡚_{Sm ⣔࡛ࡢ㌿⛣ࡣ㸰} ẁࡢ䠄ᙅ䠅ᙉ☢ᛶ㌿⛣࡛࠶ࡿ࡜⪃࠼ࡽࢀࡿ(16)_{ࠋPr ⣔} ࡛ࡣ᭱ప ࡢ_{0.36 K ࡲ࡛➨஧ࡢࣆ࣮ࢡࡣ☜ㄆࡉࢀ} ࡞࠸ࡶࡢࡢࠊప ࡛ࡢ᫂ࡽ࠿࡞ẚ⇕ࡢୖ᪼࠿ࡽ㏲ ḟⓗ┦㌿⛣ࡀ࠶ࡿ࡜⪃࠼ࡽࢀࡿࠋ_α-Tb2S3࡛ࡢ☢Ẽ ᵓ㐀ゎᯒ⤖ᯝ(19)_{࡜௚ࡢᐇ㦂஦ᐇ࠿ࡽࠊࡇࢀࡽࡢ㧗}  ഃ㌿⛣࡛ࡣ _{R1ࠊప ഃ㌿⛣࡛ࡣ R2 ࡀ⛛ᗎ໬ࡍ} ᡁ ಟ஧㸪㜿Ἴຍ ῟஧㸪⸨ ⪔୍㑻

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ࡁ࡞඲ゅ㐠ື㔞㔞Ꮚᩘࢆࡶࡘ㔜ᕼᅵ㢮ඖ⣲ࢆྵࡴ ≀㉁ࡀೃ⿵࡜࡞ࡾᚓࡿࠋ_{10 K ⛬ᗘ࡛☢Ẽ┦㌿⛣ࢆ} ࡶࡘα ኚែᕼᅵ㢮୕஧◲໬≀ α-R2S3䠄R㸸ᕼᅵ㢮ඖ ⣲䠅ࡸᕼᅵ㢮࣍࢘໬≀࡟╔┠ࡋࠊ⣔⤫ⓗ࡞ẚ⇕ ᐃ ࢆ⾜ࡗࡓࠋ  ☢Ẽ෭෾ᮦ࡟㛵ࡋ࡚ࡣືస ᗘࢆ⪃៖ࡍࡿࡇ࡜ ࡀ㔜せ࡛࠶ࡾࠊᮏࢱࢫࢡ࣓ࣥࣂ࣮ࡀࡶࡘࢩ࣮ࢬࢆ ㋃ࡲ࠼ࠊ_{(1)ᐊ ᇦࠊ(2)ᾮయ❅⣲ ᗘᇦࠊ(3)10 K} ᗘᇦ࡛ࡢ᳨ウࢆ⾜ࡗࡓࠋ  _{(1)ᐊ ᇦ㸸ᐊ ᇦ࡟࠾ࡅࡿ☢Ẽ෭෾ᶵࡣࠊࣇࣟ} ࣥ࢞ࢫ࡟ࡼࡿ࢜ࢰࣥᒙࡢ◚ቯࠊ௦᭰ࣇࣟࣥ࢞ࢫ࡟ ࡼࡿᆅ⌫ ᬮ໬ࡢಁ㐍ࢆ㜼ࡴࡶࡢ࡜ࡋ࡚ᮇᚅࡉࢀ ࡚࠸ࡿࠋࡇࡢ ᗘᇦ࡟࠾࠸࡚ࡣࠊᐊ ௜㏆࡟ᙉ☢ ᛶ㌿⛣ ᗘ䠄࣮࢟ࣗࣜⅬ䠅_TC ࢆࡶࡘᕼᅵ㢮ඖ⣲ _Gd ࡀึᮇࡢ㡭ࡼࡾὀ┠ࡉࢀ࡚ᐇᶵ࡛ࡶホ౯ࡉࢀࠊᐊ  ☢Ẽ෭෾ࢩࢫࢸ࣒ࡢⓎᒎ࡟኱ࡁ࡞ᙺ๭ࢆᢸࡗ࡚ ࡁࡓࠋ㧗ຠ⋡࣭㧗ᛶ⬟໬ࡢࡓࡵ࡟✀ࠎࡢGd ໬ྜ≀ࠊ ౛࠼ࡤ_Gd5Si2Ge2(1)(2)_{ࡸࠊ㠀☢ᛶࡢᕼᅵ㢮ඖ⣲La ࢆ} ྵࡴ La(Fe1-xSix)13Hy(3)(4)࠶ࡿ࠸ࡣᕼᅵ㢮ඖ⣲ࢆྵࡲ ࡞࠸_Mn(As1-xSbx)(5)ࡸ MnFe(P1-xAsx)(6)࡞࡝ࡀὀ┠ࢆ 㞟ࡵ࡚┒ࢇ࡟◊✲ࡉࢀࠊᐇ⏝໬࡟㏆࡙࠸࡚࠸ࡿࠋ ᕼᅵ㢮ඖ⣲ࢆ⏝࠸ࡎ࡜ࡶࠊ୍ḟ┦㌿⛣ࡢ኱ࡁ࡞࢚ ࣥࢺࣟࣆ࣮ኚ໬ࢆ฼⏝ࡍࢀࡤ㧗ᛶ⬟ࡢ෭෾ᶵࢆᐇ ⌧࡛ࡁࡿྍ⬟ᛶࡀ♧ࡉࢀࠊ⌧ᅾࡢ୍ࡘࡢ₻ὶ࡜࡞ ࡾࡘࡘ࠶ࡿࠋᚋⓎࡢᮏࢱࢫࢡ࡛ࡣࠊ⌧᭷ࡢࢩ࣮ࢬ ࡛࠶ࡿᐊ ᇦ࡛␗ᖖ࡟኱ࡁ࡞⇕⭾ᙇ⋡䠄ẚ⇕࡜ᐦ ᥋࡟㛵㐃ࡍࡿ≀⌮㔞䠅ࢆ♧ࡍᕼᅵ㢮ඖ⣲ Ce ࢆྵࡴ ᵓ㐀୙つ๎⣔ྜ㔠(7)-(9)_{ࡢᇶ♏◊✲ࢆ㐍ࡵࡓࠋ}  (2)ᾮయ❅⣲ ᗘᇦ㸸㖡㓟໬≀㧗 ㉸ఏᑟయࢆ⏝ ࠸ࡓ✀ࠎࡢࢹࣂ࢖ࢫࡀ฼⏝ࡉࢀ࡚ࡁ࡚࠸ࡿࡀࠊࡇ ࡢᏳ ᐃືసࡢ ࡓࡵ࡟ࡣ ᾮయ❅ ⣲ ᗘ 䠄❅⣲ࡢ Ἓ Ⅼ㸸_{77 K䠅ࡼࡾᩘ༑ K ప࠸ ᗘࡀᚲせ࡛࠶ࡾࠊࡇࢀ} ࢆᐇ⌧ࡍࡿపࢥࢫࢺ࣭ప᣺ື࣭ప㦁㡢ࡢᑠᆺ☢Ẽ ෭෾ᶵࡀᮃࡲࢀࡿࠋࡑࡢᙧᡂࣃࢱ࣮ࣥ࠿ࡽࢫࢺࣛ ࢖ࣉ⛛ᗎ࡜࿧ࡤࢀࡿ㟁Ⲵ⛛ᗎࢆ㉸ఏᑟ㌿⛣࡟కࡗ ࡚㉳ࡇࡍ㖡㓟໬≀㧗 ㉸ఏᑟయ࡟㛵ࡍࡿ◊✲ࢩ࣮ ࢬ(10)ࡀ࠶ࡾࠊࡇࡢ㌿⛣࡟క࠺࢚ࣥࢺࣟࣆ࣮ኚ໬ࢆ ྵࡵࡓᇶ♏◊✲࡟ྲྀࡾ⤌ࢇࡔࠋ  (3)10 K  ᗘᇦ㸸ࢡ࣮࢚ࣜࣥࢿࣝࢠ࣮࡜ࡋ࡚ᮇᚅ ࡉࢀࡿỈ⣲⇞ᩱࢆ㈓ⶶ࣭㍺㏦ࡍࡿࡓࡵ࡟ࡣỈ⣲ࢆ ᾮ໬ࡍࡿࡢࡀຠ⋡ⓗ࡛࠶ࡾࠊ10 K ⛬ᗘࡢ ᗘࢆᐇ ⌧ࡍࡿᚲせࡀ࠶ࡿࠋᾮయ࣒࣊ࣜ࢘ࢆ౑⏝ࡍࢀࡤࠊ ᾐₕࡍࡿࡔࡅ࡛࣒࣊ࣜ࢘ࡢἛⅬ 4.2 K ㏆ࡃࡲ࡛෭ ༷ࡍࡿࡇ࡜ࡀྍ⬟࡛࠶ࡿࡀࠊ࣒࣊ࣜ࢘ࡣᕼᑡ㈨※ ࡛࠶ࡾࠊ♫఍᝟ໃ࡟ࡼࡗ࡚ࡣ☜ಖࡀࡁࢃࡵ࡚ᅔ㞴 ࡟ࡶ࡞ࡾᚓࡿࠋࡇࡢࡓࡵࠊ࣒࣊ࣜ࢘ࣇ࣮࡛ࣜྠ➼ ࡢ ᗘࢆᚓࡿᑠᆺ࣭పࢥࢫࢺ࣭ప᣺ື࣭ప㦁㡢ࡢ ☢Ẽ෭෾ᶵࡢ㛤Ⓨࡀᮇᚅࡉࢀ࡚࠸ࡿࠋࡇࢀࡲ࡛ⴭ ⪅ࡣ๓㏙ࡢα-R2S3ࡀ10 K ௜㏆ࡢ ᗘ࡛㏲ḟ☢Ẽ┦ ㌿⛣ࢆ㉳ࡇࡋࠊࡑࢀ࡟కࡗ࡚✀ࠎࡢ≉␗࡞≀ᛶᛂ ⟅ࢆ♧ࡍࡇ࡜ࢆぢฟࡋ࡚ࡁࡓ(11)-(18)ࠋࡇࡢ◊✲ࢩ࣮ ࢬࢆά࠿ࡋࠊ_α-R2S3ࡢ☢Ẽ෭෾ᮦ࡜ࡋ࡚ࡢྍ⬟ᛶࢆ ᥈ࡗࡓࠋ  _α-R2S3ࡣᩳ᪉ᬗ⣔⤖ᬗᵓ㐀䠄✵㛫⩌㸸_{Pnma䠅୰࡟} ⤖ᬗᏛⓗ࡟⊂❧࡞஧ࡘࡢᕼᅵ㢮ࢧ࢖ࢺ㸦R1, R2㸧ࢆ ᭷ࡋ࡚࠸ࡿ(11)_{ࠋࡇࢀࡲ࡛࡟ᚓࡽࢀࡓᐇ㦂஦ᐇࢆ⥲} ᣓࡍࡿ࡜ࠊR1 ࡣ b ㍈᪉ྥ୍ḟඖ㙐ෆ࡛ᙉ☢ᛶⓗࠊa ㍈᪉ྥࢪࢢࢨࢢ㙐ෆ࡛཯ᙉ☢ᛶⓗ࡟⛛ᗎ໬ࡍࡿഴ ྥࡀᙉࡃࠊR1 ࡜ᙅࡃ⤖ྜࡋࡓ R2 ࡣ㊥㞳ⓗ࡟ࡣࡸ ࡸ㐲࠸㞄᥋ _{R2 ࡜」㞧࡟స⏝ࡋྜ࠺࡜⪃ᐹࡉࢀࡿࠋ} ࡇࡢR1-R2, R2-R2 㛫ࡢ」㞧࡞☢Ẽⓗ┦஫స⏝ࡀ➇ ྜࡋࠊ ᗘࡸ☢ሙ࡟ᑐࡋ࡚࣐ࢡࣟ≀ᛶࡀ≉␗࡞ᛂ ⟅ࢆ♧ࡍ࡜⪃࠼ࡽࢀࡿࠋᮏሗ࿌࡛ࡣࠊα-R2S3ࡢ↓☢ ሙୗ࠾ࡼࡧ☢ሙ୰࡛ࡢẚ⇕ࡢ ᐃ⤖ᯝ࡜⵳෭ᮦ࣭ ☢Ẽ෭෾ᮦ࡜ࡋ࡚ࡢྍ⬟ᛶ࡟ࡘ࠸࡚㆟ㄽࡍࡿࠋ 3 ᐇ㦂  ᕷ㈍ࡢᕼᅵ㢮㓟໬≀ࢆ _CS2Ẽὶ୰࡛ຍ⇕ࡍࡿࡇ ࡜࡛ α-R2S3⢊ᮎヨᩱࢆᚓࠊࡇࢀࢆཎᩱ࡜ࡋ࡚ࣚ࢘ ⣲ࢆ㍺㏦๣࡜ࡋࡓẼ┦໬Ꮫ㍺㏦ἲ࡟ࡼࡾ༢⤖ᬗヨ ᩱࢆ⫱ᡂࡋࡓࠋẚ⇕ࡣ⡿ᅜ_{Quantum Design ♫〇≀} ⌮≉ᛶ ᐃࢩࢫࢸ࣒ _{PPMS ࢆ౑⏝ࡋࠊ5 T ࡲ࡛ࡢ} ✀ࠎࡢ☢ሙ୰࡛⦆࿴ἲ࡟ࡼࡾ ᐃࡋࡓࠋ 4 ⤖ᯝ࡜⪃ᐹ 4.1 ↓☢ሙୗẚ⇕  ᅗ_{1 ࡟ α-R2S3}䠄_{R㸸Pr, Nd, Sm, Gd, Tb, Dy䠅༢⤖ᬗ} ࡢ↓☢ሙୗ࡛ࡢẚ⇕ࡢ ᗘ౫Ꮡᛶࢆ♧ࡍࠋGd, Pr ⣔௨እࡢ _α-R2S3࡛ࡣ㸰ẁࡢ☢Ẽ┦㌿⛣࡟క࠺ඛ㗦 ࡞ࣆ࣮ࢡࡀ☜ㄆࡉࢀࡿࠋTb, Dy ⣔࡟㛵ࡋ࡚ࡣ☢໬  ᐃ(12)(14)_{ࡸ୰ᛶᏊᅇᢡᐇ㦂}(19)_{ࡢ⤖ᯝ࠿ࡽࠊ㸰ẁࡢ} ཯ᙉ☢ᛶ㌿⛣ࡀ㉳ࡁ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿࠋNd ⣔ࡢ ᑡ࡞ࡃ࡜ࡶ㧗 ഃࣆ࣮ࢡࡣࡸࡣࡾ཯ᙉ☢ᛶ㌿⛣࡟ ࡼࡿࡶࡢ࡛࠶ࡿࠋࡇࢀ࡟ᑐࡋ࡚Sm ⣔࡛ࡢ㌿⛣ࡣ㸰 ẁࡢ䠄ᙅ䠅ᙉ☢ᛶ㌿⛣࡛࠶ࡿ࡜⪃࠼ࡽࢀࡿ(16)_{ࠋPr ⣔} ࡛ࡣ᭱ప ࡢ0.36 K ࡲ࡛➨஧ࡢࣆ࣮ࢡࡣ☜ㄆࡉࢀ ࡞࠸ࡶࡢࡢࠊప ࡛ࡢ᫂ࡽ࠿࡞ẚ⇕ࡢୖ᪼࠿ࡽ㏲ ḟⓗ┦㌿⛣ࡀ࠶ࡿ࡜⪃࠼ࡽࢀࡿࠋα-Tb2S3࡛ࡢ☢Ẽ ᵓ㐀ゎᯒ⤖ᯝ(19)_{࡜௚ࡢᐇ㦂஦ᐇ࠿ࡽࠊࡇࢀࡽࡢ㧗}  ഃ㌿⛣࡛ࡣ R1ࠊప ഃ㌿⛣࡛ࡣ R2 ࡀ⛛ᗎ໬ࡍ 㧗ᛶ⬟☢Ẽ⇕ኚ᥮ᮦᩱࡢ㛤Ⓨࢆ┠ᣦࡋ࡚

- 35 -

ࡿ࡜㢮᥎ࡉࢀࡿࠋ୍᪉࡛୰ᛶᏊᅇᢡᐇ㦂(20)ࡸ࢚ࣥ ࢺࣟࣆ࣮ኚ໬(21)_{࠿ࡽ☜ㄆࡉࢀࡿࡼ࠺࡟ࠊα-Gd2S3ࡣ} 㸯ẁࡢ㌿⛣࡛Gd1, Gd2 ࡀ཯ᙉ☢ᛶ⛛ᗎ໬ࡍࡿࠋ 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0 5 10 15 20

C

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m

-3

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R

2

S

3 R = Gd Tb Dy Pr Nd Sm ᅗ_{1 α-R2S3}༢⤖ᬗࡢẚ⇕ࡢ ᗘ౫Ꮡᛶ  ᅗ_{1 ࠿ࡽ᫂ࡽ࠿࡞ࡼ࠺࡟ࠊα-Gd2S3}ࡢẚ⇕ࣆ࣮ࢡ ࡣ௚ࢆᅽಽࡋ࡚኱ࡁ࠸ࠋከ㔜㡯ᇶᗏ≧ែ࡟࠾࠸࡚ Gd3+_{ࡢ඲ゅ㐠ື㔞J ࡣ 7/2 ࡜ẚ㍑ⓗ኱ࡁ࠸ࡀࠊTb}3+ (J = 6)ࡸ Dy3+ _{(J = 15/2)ࡢ᪉ࡀࡉࡽ࡟኱ࡁ࠸ࠋࡋ࠿ࡋࠊ} Gd ⣔௨እࡢ J ከ㔜㡯ࡣ⤖ᬗሙ࡟ࡼࡗ࡚࢚ࢿࣝࢠ࣮ ‽఩ศ⿣ࡋࠊᇶᗏ㡯ࡢከ㔜ᗘࡣపࡃ࡞ࡿࠋ୍᪉_Gd ⣔࡛ࡣ㌶㐨ゅ㐠ື㔞ࡀ _{0 ࡛࠶ࡿࡓࡵ࡟⤖ᬗሙࡢᙳ} 㡪ࢆཷࡅࡎࠊᇶᗏࡀࢫࣆࣥ _{8 㔜㡯࡛࠶ࡿࡇ࡜࡟㉳} ᅉࡋ࡚ẚ⇕ࣆ࣮ࢡࡀ኱ࡁࡃ࡞ࡗ࡚࠸ࡿࠋࡉࡽ࡟_Gd ⣔࡛ࡣ㌿⛣ࡼࡾప ࡛ẚ⇕ࡀ⫪ࢆࡶࡗ࡚࠸ࡿࠋࡇ ࢀࡣᗄఱᏛⓗࣇࣛࢫࢺ࣮ࣞࢩࣙࣥࢆ᭷ࡍࡿ_{Gd2 ࡢ} ⛛ᗎ໬ࡀ_{Gd1 ࡢ⮬Ⓨ⛛ᗎ࡟ࡼࡿศᏊሙࡢᙳ㡪࡛ࠊ}  ᗘపୗ࡟కࡗ࡚ᚎࠎ࡟㐍⾜ࡋ࡚࠸ࡿࡇ࡜࡟㉳ᅉ ࡋ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿ(21)_{ࠋࡇࡢࡓࡵࠊα-Gd2S3ࡣᗈ} ࠸ ᗘ⠊ᅖ࡛኱ࡁ࡞ẚ⇕ࢆࡶࡘࠋ༢఩య✚࠶ࡓࡾ ࡢẚ⇕ࡢ᭱኱್_{0.63 J K}-1_cm-3 _{(T = 9.8 K)ࡣ⵳෭ᮦ} ࡜ ࡋ ࡚ ᮇ ᚅ ࡉ ࢀ ࡚ ࠸ ࡿ _{Gd2O2S (GOS) ࡢ 1.1} J K-1_cm-3 _{(T = 5.2 K)ࡼࡾࡶప࠸ࡀࠊᐇ⏝໬ࡉࢀ࡚࠸} ࡿ_{Er3Ni ࡸ HoCu2}ࢆ෽㥙ࡋ࡚࠸ࡿࠋ_HoCu2ࡀࢲࣈࣝ ࣆ࣮ࢡ࡛ࡼ࠸ᛶ⬟ࢆ♧ࡍ ᗘᇦ࡛ࡣ್ࡀୗᅇࡿࡀ α-Gd2S3ࡢᖜᗈࡢ⫪ࡣⰋ࠸≉ᚩ࡛࠶ࡿࠋࡲࡓࠊࡼࡾ ኱ࡁ࡞ẚ⇕ࣆ࣮ࢡࢆࡶࡘᙉ☢ᛶయ _{ErNi ࡛ࡣ࡞ࡃ} Er3Ni ࡀᐇ⏝໬ࡉࢀ࡚࠸ࡿ⌮⏤ࡣᚋ⪅ࡀ཯ᙉ☢ᛶయ ࡛࠶ࡾ㉸ఏᑟ࣐ࢢࢿࢵࢺ࠿ࡽࡢ₃ࢀ☢ሙࡢᙳ㡪ࢆ ཷࡅ࡟ࡃ࠸ࡓࡵ࡛࠶ࡿࡀࠊࡑࡢⅬ࡛ࡶ཯ᙉ☢ᛶయ α-Gd2S3ࡣ㐺ࡋ࡚࠸ࡿࠋ኱ࡁ࡞ẚ⇕ࢆ♧ࡍ ᗘᇦࡀ ␗࡞ࡿ⵳෭ᮦࢆ⤌ࡳྜࢃࡏ࡚෭෾ᶵ➼࡟඘ሸࡍࡿ ࡇ࡜࡟ࡼࡾ㧗ຠ⋡໬ࡀᅗࢀࡿࡓࡵࠊࢲࣈࣝࣆ࣮ࢡ ࢆ♧ࡍ௚ࡢ α-R2S3ࡶྵࡵࠊẚ⇕≉ᛶⓗ࡟ࡣ⵳෭ᮦ ࡜ࡋ࡚ࡢྍ⬟ᛶࡣ࠶ࡿࠋࡋ࠿ࡋᐇᮦᩱ࡜ࡋ࡚ࡣࠊ ⌫≧ከ⤖ᬗヨᩱࡢసᡂྍ⬟ᛶࠊࡑࡢሙྜࡢẚ⇕≉ ᛶࡸ⇕ఏᑟ⋡ࠊ⇕ࢧ࢖ࢡࣝࢆྵࡵࡓ⪏⎔ቃᛶࠊࢥ ࢫࢺ➼ࡢ᳨ウࡍ࡭ࡁㄢ㢟ࡣᩘከࡃᏑᅾࡍࡿࠋ 4.2 ☢ሙ୰ẚ⇕  ᅗ2 ࡟ α-Dy2S3ࡢb ㍈࡟ᑐࡋ࡚ᆶ┤࡟☢ሙࢆ༳ຍ ࡋࡓሙྜࡢ_{(a)☢Ẽẚ⇕ Cm}࠾ࡼࡧ_{(b)☢Ẽ࢚ࣥࢺࣟ} ࣆ࣮Smࡢ ᗘ౫Ꮡᛶࢆ♧ࡍࠋ㧗 ഃ㌿⛣ⅬTN1ࡀ☢ ሙ༳ຍ࡟ࡼࡾ㢧ⴭ࡟㧗 ഃ࡟ࢩࣇࢺࡋࠊప ഃ㌿ ⛣ࡀᾘኻࡋ࡚࠸ࡿᵝᏊࡀࢃ࠿ࡿࠋᙉ☢ᛶ㌿⛣ࡀ☢ ሙ༳ຍ࡟ࡼࡾ㧗 ഃ࡟ࢩࣇࢺࡍࡿࡇ࡜ࡣࡼࡃぢࡽ ࢀࡿࡇ࡜࡛ࠊࡇࡢഴྥࡣ☢Ẽ෭෾࡟࡜ࡗ࡚ࡣ㒔ྜ ࡀⰋ࠸ࠋࡋ࠿ࡋࠊ཯ᙉ☢ᛶ㌿⛣ࡣ☢ሙ༳ຍ࡟ࡼࡾ ప ഃ࡟ࢩࣇࢺࡍࡿࡢࡀ୍⯡ⓗ࡛࠶ࡿࠋ⌧࡟௚ࡢ α-R2S3࡛ࡣ☢ሙࡢ༳ຍ᪉ྥ࡟ࡼࡽࡎ㌿⛣ࡢప ࢩ ࣇࢺࡀほ ࡉࢀࡿࡋࠊα-Dy2S3ࡢb ㍈࡟ᖹ⾜࡞☢ሙ ༳ຍ࡛ࡶྠᵝࡢഴྥࡀぢࡽࢀࡿࠋ_α-Dy2S3ࡣ㏲ḟ཯ ᙉ☢ᛶ㌿⛣Ⅼࡢ㛫TN1-TN2࡛✀ࠎࡢ≉␗࡞⌧㇟ࢆ♧ ࡍ(13)(14)_{ࡀࠊb ㍈࡟ᆶ┤࡞☢ሙ࡟ᑐࡍࡿᛂ⟅ࡀ㗦ᩄ} ࡛࠶ࡿࡇ࡜ࡶࡑࡢ୍ࡘ࡛࠶ࡿࠋDy1 ࡀ཯ᙉ☢ᛶ⛛ ᗎ໬ࡍࡿࡇ࡜࡟ࡼࡾࠊ_{Dy2 ࡢ☢ሙ࡟ᑐࡍࡿᛂ⟅ᛶ} ࡀࡼࡃ࡞ࡾࠊ☢ሙ࡟ࡼࡿࢮ࣮࣐࢚ࣥࢿࣝࢠ࣮పୗ ࡀ࠶ࡿࡓࡵ࡟ࠊ_TN1ࡀ㧗 ࢩࣇࢺࡍࡿ࡜⪃࠼ࡽࢀࡿࠋ 0 10 20 30 40 50

-

Dy₂

S

₃

C

m

/ J

K

-1

mol

-1

Hԋb

0 T 1 T2 T 3 T 5 T

(a)

0 5 10 15 20 0 5 10 15 20

-

Dy₂

S

₃

S

m

/ J

K

-1

mol

-1

Hԋb

0 T1 T 2 T 5 T 3 T

(b)

T / K

ᅗ_{2 α-R}2S3༢⤖ᬗࡢ☢ሙ୰࡛ࡢ(a)☢Ẽẚ⇕࡜ (b)☢Ẽ࢚ࣥࢺࣟࣆ࣮ࡢ ᗘ౫Ꮡᛶ  _TN1ࡢ㧗 ࢩࣇࢺ࡜ప ഃ_TN2࡛ࡢ㌿⛣ࡢᾘኻࡀ ࡜ࡶ࡟ຠ࠸࡚ࠊᅗ_{2(b)࡟♧ࡍࡼ࠺࡟ C}m/T ࢆ ᐃ᭱ ప ᗘ _{0.4 K ࠿ࡽ ᗘ࡛✚ศࡋࡓ☢Ẽ࢚ࣥࢺࣟࣆ} ࣮ࡣ☢ሙ༳ຍ࡟ࡼࡾῶᑡࡋ࡚࠸ࡿ㸦_|Sm| < 0㸧ࠋບ ☢࡟Ọஂ☢▼ࡢ฼⏝ࢆ᝿ᐃࡋࡓ☢ሙ _{2 T ࡛ࡢ|Sm|}

－　35　－ 㧗ᛶ⬟☢Ẽ⇕ኚ᥮ᮦᩱࡢ㛤Ⓨࢆ┠ᣦࡋ࡚

- 35 -

ࡿ࡜㢮᥎ࡉࢀࡿࠋ୍᪉࡛୰ᛶᏊᅇᢡᐇ㦂(20)_ࡸ࢚ࣥ ࢺࣟࣆ࣮ኚ໬(21)_{࠿ࡽ☜ㄆࡉࢀࡿࡼ࠺࡟ࠊα-Gd2S3ࡣ} 㸯ẁࡢ㌿⛣࡛_{Gd1, Gd2 ࡀ཯ᙉ☢ᛶ⛛ᗎ໬ࡍࡿࠋ} 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0 5 10 15 20

C

/ J

K

-1

c

m

-3

T / K

-

R

2

S

3 R = Gd Tb Dy Pr Nd Sm ᅗ_{1 α-R2S3}༢⤖ᬗࡢẚ⇕ࡢ ᗘ౫Ꮡᛶ  ᅗ_{1 ࠿ࡽ᫂ࡽ࠿࡞ࡼ࠺࡟ࠊα-Gd2S3}ࡢẚ⇕ࣆ࣮ࢡ ࡣ௚ࢆᅽಽࡋ࡚኱ࡁ࠸ࠋከ㔜㡯ᇶᗏ≧ែ࡟࠾࠸࡚ Gd3+_{ࡢ඲ゅ㐠ື㔞J ࡣ 7/2 ࡜ẚ㍑ⓗ኱ࡁ࠸ࡀࠊTb}3+ (J = 6)ࡸ Dy3+ _{(J = 15/2)ࡢ᪉ࡀࡉࡽ࡟኱ࡁ࠸ࠋࡋ࠿ࡋࠊ} Gd ⣔௨እࡢ J ከ㔜㡯ࡣ⤖ᬗሙ࡟ࡼࡗ࡚࢚ࢿࣝࢠ࣮ ‽఩ศ⿣ࡋࠊᇶᗏ㡯ࡢከ㔜ᗘࡣపࡃ࡞ࡿࠋ୍᪉Gd ⣔࡛ࡣ㌶㐨ゅ㐠ື㔞ࡀ _{0 ࡛࠶ࡿࡓࡵ࡟⤖ᬗሙࡢᙳ} 㡪ࢆཷࡅࡎࠊᇶᗏࡀࢫࣆࣥ 8 㔜㡯࡛࠶ࡿࡇ࡜࡟㉳ ᅉࡋ࡚ẚ⇕ࣆ࣮ࢡࡀ኱ࡁࡃ࡞ࡗ࡚࠸ࡿࠋࡉࡽ࡟_Gd ⣔࡛ࡣ㌿⛣ࡼࡾప ࡛ẚ⇕ࡀ⫪ࢆࡶࡗ࡚࠸ࡿࠋࡇ ࢀࡣᗄఱᏛⓗࣇࣛࢫࢺ࣮ࣞࢩࣙࣥࢆ᭷ࡍࡿ_{Gd2 ࡢ} ⛛ᗎ໬ࡀGd1 ࡢ⮬Ⓨ⛛ᗎ࡟ࡼࡿศᏊሙࡢᙳ㡪࡛ࠊ  ᗘపୗ࡟కࡗ࡚ᚎࠎ࡟㐍⾜ࡋ࡚࠸ࡿࡇ࡜࡟㉳ᅉ ࡋ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿ(21)ࠋࡇࡢࡓࡵࠊα-Gd2S3ࡣᗈ ࠸ ᗘ⠊ᅖ࡛኱ࡁ࡞ẚ⇕ࢆࡶࡘࠋ༢఩య✚࠶ࡓࡾ ࡢẚ⇕ࡢ᭱኱್0.63 J K-1cm-3 (T = 9.8 K)ࡣ⵳෭ᮦ ࡜ ࡋ ࡚ ᮇ ᚅ ࡉ ࢀ ࡚ ࠸ ࡿ _{Gd2O2S (GOS) ࡢ 1.1} J K-1_cm-3 _{(T = 5.2 K)ࡼࡾࡶప࠸ࡀࠊᐇ⏝໬ࡉࢀ࡚࠸} ࡿ_{Er3Ni ࡸ HoCu2}ࢆ෽㥙ࡋ࡚࠸ࡿࠋ_HoCu2ࡀࢲࣈࣝ ࣆ࣮ࢡ࡛ࡼ࠸ᛶ⬟ࢆ♧ࡍ ᗘᇦ࡛ࡣ್ࡀୗᅇࡿࡀ α-Gd2S3ࡢᖜᗈࡢ⫪ࡣⰋ࠸≉ᚩ࡛࠶ࡿࠋࡲࡓࠊࡼࡾ ኱ࡁ࡞ẚ⇕ࣆ࣮ࢡࢆࡶࡘᙉ☢ᛶయ _{ErNi ࡛ࡣ࡞ࡃ} Er3Ni ࡀᐇ⏝໬ࡉࢀ࡚࠸ࡿ⌮⏤ࡣᚋ⪅ࡀ཯ᙉ☢ᛶయ ࡛࠶ࡾ㉸ఏᑟ࣐ࢢࢿࢵࢺ࠿ࡽࡢ₃ࢀ☢ሙࡢᙳ㡪ࢆ ཷࡅ࡟ࡃ࠸ࡓࡵ࡛࠶ࡿࡀࠊࡑࡢⅬ࡛ࡶ཯ᙉ☢ᛶయ α-Gd2S3ࡣ㐺ࡋ࡚࠸ࡿࠋ኱ࡁ࡞ẚ⇕ࢆ♧ࡍ ᗘᇦࡀ ␗࡞ࡿ⵳෭ᮦࢆ⤌ࡳྜࢃࡏ࡚෭෾ᶵ➼࡟඘ሸࡍࡿ ࡇ࡜࡟ࡼࡾ㧗ຠ⋡໬ࡀᅗࢀࡿࡓࡵࠊࢲࣈࣝࣆ࣮ࢡ ࢆ♧ࡍ௚ࡢ _α-R2S3ࡶྵࡵࠊẚ⇕≉ᛶⓗ࡟ࡣ⵳෭ᮦ ࡜ࡋ࡚ࡢྍ⬟ᛶࡣ࠶ࡿࠋࡋ࠿ࡋᐇᮦᩱ࡜ࡋ࡚ࡣࠊ ⌫≧ከ⤖ᬗヨᩱࡢసᡂྍ⬟ᛶࠊࡑࡢሙྜࡢẚ⇕≉ ᛶࡸ⇕ఏᑟ⋡ࠊ⇕ࢧ࢖ࢡࣝࢆྵࡵࡓ⪏⎔ቃᛶࠊࢥ ࢫࢺ➼ࡢ᳨ウࡍ࡭ࡁㄢ㢟ࡣᩘከࡃᏑᅾࡍࡿࠋ 4.2 ☢ሙ୰ẚ⇕  ᅗ_{2 ࡟ α-Dy2S3}ࡢ_{b ㍈࡟ᑐࡋ࡚ᆶ┤࡟☢ሙࢆ༳ຍ} ࡋࡓሙྜࡢ_{(a)☢Ẽẚ⇕ C}m࠾ࡼࡧ(b)☢Ẽ࢚ࣥࢺࣟ ࣆ࣮_Smࡢ ᗘ౫Ꮡᛶࢆ♧ࡍࠋ㧗 ഃ㌿⛣Ⅼ_TN1ࡀ☢ ሙ༳ຍ࡟ࡼࡾ㢧ⴭ࡟㧗 ഃ࡟ࢩࣇࢺࡋࠊప ഃ㌿ ⛣ࡀᾘኻࡋ࡚࠸ࡿᵝᏊࡀࢃ࠿ࡿࠋᙉ☢ᛶ㌿⛣ࡀ☢ ሙ༳ຍ࡟ࡼࡾ㧗 ഃ࡟ࢩࣇࢺࡍࡿࡇ࡜ࡣࡼࡃぢࡽ ࢀࡿࡇ࡜࡛ࠊࡇࡢഴྥࡣ☢Ẽ෭෾࡟࡜ࡗ࡚ࡣ㒔ྜ ࡀⰋ࠸ࠋࡋ࠿ࡋࠊ཯ᙉ☢ᛶ㌿⛣ࡣ☢ሙ༳ຍ࡟ࡼࡾ ప ഃ࡟ࢩࣇࢺࡍࡿࡢࡀ୍⯡ⓗ࡛࠶ࡿࠋ⌧࡟௚ࡢ α-R2S3࡛ࡣ☢ሙࡢ༳ຍ᪉ྥ࡟ࡼࡽࡎ㌿⛣ࡢప ࢩ ࣇࢺࡀほ ࡉࢀࡿࡋࠊ_α-Dy2S3ࡢ_{b ㍈࡟ᖹ⾜࡞☢ሙ} ༳ຍ࡛ࡶྠᵝࡢഴྥࡀぢࡽࢀࡿࠋα-Dy2S3ࡣ㏲ḟ཯ ᙉ☢ᛶ㌿⛣Ⅼࡢ㛫_TN1-TN2࡛✀ࠎࡢ≉␗࡞⌧㇟ࢆ♧ ࡍ(13)(14)_{ࡀࠊb ㍈࡟ᆶ┤࡞☢ሙ࡟ᑐࡍࡿᛂ⟅ࡀ㗦ᩄ} ࡛࠶ࡿࡇ࡜ࡶࡑࡢ୍ࡘ࡛࠶ࡿࠋ_{Dy1 ࡀ཯ᙉ☢ᛶ⛛} ᗎ໬ࡍࡿࡇ࡜࡟ࡼࡾࠊ_{Dy2 ࡢ☢ሙ࡟ᑐࡍࡿᛂ⟅ᛶ} ࡀࡼࡃ࡞ࡾࠊ☢ሙ࡟ࡼࡿࢮ࣮࣐࢚ࣥࢿࣝࢠ࣮పୗ ࡀ࠶ࡿࡓࡵ࡟ࠊTN1ࡀ㧗 ࢩࣇࢺࡍࡿ࡜⪃࠼ࡽࢀࡿࠋ 0 10 20 30 40 50

-

Dy

₂

S

₃

C

m

/ J

K

-1

mol

-1

Hԋb

0 T 1 T2 T 3 T 5 T

(a)

0 5 10 15 20 0 5 10 15 20

-

Dy

₂

S

₃

S

m

/ J

K

-1

mol

-1

Hԋb

0 T1 T 2 T 5 T 3 T

(b)

T / K

ᅗ2 α-R2S3༢⤖ᬗࡢ☢ሙ୰࡛ࡢ(a)☢Ẽẚ⇕࡜ (b)☢Ẽ࢚ࣥࢺࣟࣆ࣮ࡢ ᗘ౫Ꮡᛶ  _TN1ࡢ㧗 ࢩࣇࢺ࡜ప ഃ_TN2࡛ࡢ㌿⛣ࡢᾘኻࡀ ࡜ࡶ࡟ຠ࠸࡚ࠊᅗ2(b)࡟♧ࡍࡼ࠺࡟ Cm/T ࢆ ᐃ᭱ ప ᗘ _{0.4 K ࠿ࡽ ᗘ࡛✚ศࡋࡓ☢Ẽ࢚ࣥࢺࣟࣆ} ࣮ࡣ☢ሙ༳ຍ࡟ࡼࡾῶᑡࡋ࡚࠸ࡿ㸦|Sm| < 0㸧ࠋບ ☢࡟Ọஂ☢▼ࡢ฼⏝ࢆ᝿ᐃࡋࡓ☢ሙ _{2 T ࡛ࡢ|Sm|} ᡁ ಟ஧㸪㜿Ἴຍ ῟஧㸪⸨ ⪔୍㑻

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ࡁ࡞඲ゅ㐠ື㔞㔞Ꮚᩘࢆࡶࡘ㔜ᕼᅵ㢮ඖ⣲ࢆྵࡴ ≀㉁ࡀೃ⿵࡜࡞ࡾᚓࡿࠋ_{10 K ⛬ᗘ࡛☢Ẽ┦㌿⛣ࢆ} ࡶࡘ_{α ኚែᕼᅵ㢮୕஧◲໬≀ α-R2S3}䠄_{R㸸ᕼᅵ㢮ඖ} ⣲䠅ࡸᕼᅵ㢮࣍࢘໬≀࡟╔┠ࡋࠊ⣔⤫ⓗ࡞ẚ⇕ ᐃ ࢆ⾜ࡗࡓࠋ  ☢Ẽ෭෾ᮦ࡟㛵ࡋ࡚ࡣືస ᗘࢆ⪃៖ࡍࡿࡇ࡜ ࡀ㔜せ࡛࠶ࡾࠊᮏࢱࢫࢡ࣓ࣥࣂ࣮ࡀࡶࡘࢩ࣮ࢬࢆ ㋃ࡲ࠼ࠊ_{(1)ᐊ ᇦࠊ(2)ᾮయ❅⣲ ᗘᇦࠊ(3)10 K} ᗘᇦ࡛ࡢ᳨ウࢆ⾜ࡗࡓࠋ  _{(1)ᐊ ᇦ㸸ᐊ ᇦ࡟࠾ࡅࡿ☢Ẽ෭෾ᶵࡣࠊࣇࣟ} ࣥ࢞ࢫ࡟ࡼࡿ࢜ࢰࣥᒙࡢ◚ቯࠊ௦᭰ࣇࣟࣥ࢞ࢫ࡟ ࡼࡿᆅ⌫ ᬮ໬ࡢಁ㐍ࢆ㜼ࡴࡶࡢ࡜ࡋ࡚ᮇᚅࡉࢀ ࡚࠸ࡿࠋࡇࡢ ᗘᇦ࡟࠾࠸࡚ࡣࠊᐊ ௜㏆࡟ᙉ☢ ᛶ㌿⛣ ᗘ䠄࣮࢟ࣗࣜⅬ䠅TC ࢆࡶࡘᕼᅵ㢮ඖ⣲ Gd ࡀึᮇࡢ㡭ࡼࡾὀ┠ࡉࢀ࡚ᐇᶵ࡛ࡶホ౯ࡉࢀࠊᐊ  ☢Ẽ෭෾ࢩࢫࢸ࣒ࡢⓎᒎ࡟኱ࡁ࡞ᙺ๭ࢆᢸࡗ࡚ ࡁࡓࠋ㧗ຠ⋡࣭㧗ᛶ⬟໬ࡢࡓࡵ࡟✀ࠎࡢ_{Gd ໬ྜ≀ࠊ} ౛࠼ࡤ_Gd5Si2Ge2(1)(2)ࡸࠊ㠀☢ᛶࡢᕼᅵ㢮ඖ⣲La ࢆ ྵࡴ _{La(Fe1-xSix)13Hy}(3)(4)_{࠶ࡿ࠸ࡣᕼᅵ㢮ඖ⣲ࢆྵࡲ} ࡞࠸_Mn(As1-xSbx)(5)ࡸ MnFe(P1-xAsx)(6)࡞࡝ࡀὀ┠ࢆ 㞟ࡵ࡚┒ࢇ࡟◊✲ࡉࢀࠊᐇ⏝໬࡟㏆࡙࠸࡚࠸ࡿࠋ ᕼᅵ㢮ඖ⣲ࢆ⏝࠸ࡎ࡜ࡶࠊ୍ḟ┦㌿⛣ࡢ኱ࡁ࡞࢚ ࣥࢺࣟࣆ࣮ኚ໬ࢆ฼⏝ࡍࢀࡤ㧗ᛶ⬟ࡢ෭෾ᶵࢆᐇ ⌧࡛ࡁࡿྍ⬟ᛶࡀ♧ࡉࢀࠊ⌧ᅾࡢ୍ࡘࡢ₻ὶ࡜࡞ ࡾࡘࡘ࠶ࡿࠋᚋⓎࡢᮏࢱࢫࢡ࡛ࡣࠊ⌧᭷ࡢࢩ࣮ࢬ ࡛࠶ࡿᐊ ᇦ࡛␗ᖖ࡟኱ࡁ࡞⇕⭾ᙇ⋡䠄ẚ⇕࡜ᐦ ᥋࡟㛵㐃ࡍࡿ≀⌮㔞䠅ࢆ♧ࡍᕼᅵ㢮ඖ⣲ _{Ce ࢆྵࡴ} ᵓ㐀୙つ๎⣔ྜ㔠(7)-(9)_{ࡢᇶ♏◊✲ࢆ㐍ࡵࡓࠋ}  _{(2)ᾮయ❅⣲ ᗘᇦ㸸㖡㓟໬≀㧗 ㉸ఏᑟయࢆ⏝} ࠸ࡓ✀ࠎࡢࢹࣂ࢖ࢫࡀ฼⏝ࡉࢀ࡚ࡁ࡚࠸ࡿࡀࠊࡇ ࡢᏳ ᐃືసࡢ ࡓࡵ࡟ࡣ ᾮయ❅ ⣲ ᗘ 䠄❅⣲ࡢ Ἓ Ⅼ㸸_{77 K䠅ࡼࡾᩘ༑ K ప࠸ ᗘࡀᚲせ࡛࠶ࡾࠊࡇࢀ} ࢆᐇ⌧ࡍࡿపࢥࢫࢺ࣭ప᣺ື࣭ప㦁㡢ࡢᑠᆺ☢Ẽ ෭෾ᶵࡀᮃࡲࢀࡿࠋࡑࡢᙧᡂࣃࢱ࣮ࣥ࠿ࡽࢫࢺࣛ ࢖ࣉ⛛ᗎ࡜࿧ࡤࢀࡿ㟁Ⲵ⛛ᗎࢆ㉸ఏᑟ㌿⛣࡟కࡗ ࡚㉳ࡇࡍ㖡㓟໬≀㧗 ㉸ఏᑟయ࡟㛵ࡍࡿ◊✲ࢩ࣮ ࢬ(10)_{ࡀ࠶ࡾࠊࡇࡢ㌿⛣࡟క࠺࢚ࣥࢺࣟࣆ࣮ኚ໬ࢆ} ྵࡵࡓᇶ♏◊✲࡟ྲྀࡾ⤌ࢇࡔࠋ  _{(3)10 K  ᗘᇦ㸸ࢡ࣮࢚ࣜࣥࢿࣝࢠ࣮࡜ࡋ࡚ᮇᚅ} ࡉࢀࡿỈ⣲⇞ᩱࢆ㈓ⶶ࣭㍺㏦ࡍࡿࡓࡵ࡟ࡣỈ⣲ࢆ ᾮ໬ࡍࡿࡢࡀຠ⋡ⓗ࡛࠶ࡾࠊ_{10 K ⛬ᗘࡢ ᗘࢆᐇ} ⌧ࡍࡿᚲせࡀ࠶ࡿࠋᾮయ࣒࣊ࣜ࢘ࢆ౑⏝ࡍࢀࡤࠊ ᾐₕࡍࡿࡔࡅ࡛࣒࣊ࣜ࢘ࡢἛⅬ _{4.2 K ㏆ࡃࡲ࡛෭} ༷ࡍࡿࡇ࡜ࡀྍ⬟࡛࠶ࡿࡀࠊ࣒࣊ࣜ࢘ࡣᕼᑡ㈨※ ࡛࠶ࡾࠊ♫఍᝟ໃ࡟ࡼࡗ࡚ࡣ☜ಖࡀࡁࢃࡵ࡚ᅔ㞴 ࡟ࡶ࡞ࡾᚓࡿࠋࡇࡢࡓࡵࠊ࣒࣊ࣜ࢘ࣇ࣮࡛ࣜྠ➼ ࡢ ᗘࢆᚓࡿᑠᆺ࣭పࢥࢫࢺ࣭ప᣺ື࣭ప㦁㡢ࡢ ☢Ẽ෭෾ᶵࡢ㛤Ⓨࡀᮇᚅࡉࢀ࡚࠸ࡿࠋࡇࢀࡲ࡛ⴭ ⪅ࡣ๓㏙ࡢ_α-R2S3ࡀ_{10 K ௜㏆ࡢ ᗘ࡛㏲ḟ☢Ẽ┦} ㌿⛣ࢆ㉳ࡇࡋࠊࡑࢀ࡟కࡗ࡚✀ࠎࡢ≉␗࡞≀ᛶᛂ ⟅ࢆ♧ࡍࡇ࡜ࢆぢฟࡋ࡚ࡁࡓ(11)-(18)_{ࠋࡇࡢ◊✲ࢩ࣮} ࢬࢆά࠿ࡋࠊα-R2S3ࡢ☢Ẽ෭෾ᮦ࡜ࡋ࡚ࡢྍ⬟ᛶࢆ ᥈ࡗࡓࠋ  α-R2S3ࡣᩳ᪉ᬗ⣔⤖ᬗᵓ㐀䠄✵㛫⩌㸸Pnma䠅୰࡟ ⤖ᬗᏛⓗ࡟⊂❧࡞஧ࡘࡢᕼᅵ㢮ࢧ࢖ࢺ㸦_{R1, R2㸧ࢆ} ᭷ࡋ࡚࠸ࡿ(11)_{ࠋࡇࢀࡲ࡛࡟ᚓࡽࢀࡓᐇ㦂஦ᐇࢆ⥲} ᣓࡍࡿ࡜ࠊ_{R1 ࡣ b ㍈᪉ྥ୍ḟඖ㙐ෆ࡛ᙉ☢ᛶⓗࠊa} ㍈᪉ྥࢪࢢࢨࢢ㙐ෆ࡛཯ᙉ☢ᛶⓗ࡟⛛ᗎ໬ࡍࡿഴ ྥࡀᙉࡃࠊ_{R1 ࡜ᙅࡃ⤖ྜࡋࡓ R2 ࡣ㊥㞳ⓗ࡟ࡣࡸ} ࡸ㐲࠸㞄᥋ R2 ࡜」㞧࡟స⏝ࡋྜ࠺࡜⪃ᐹࡉࢀࡿࠋ ࡇࡢ_{R1-R2, R2-R2 㛫ࡢ」㞧࡞☢Ẽⓗ┦஫స⏝ࡀ➇} ྜࡋࠊ ᗘࡸ☢ሙ࡟ᑐࡋ࡚࣐ࢡࣟ≀ᛶࡀ≉␗࡞ᛂ ⟅ࢆ♧ࡍ࡜⪃࠼ࡽࢀࡿࠋᮏሗ࿌࡛ࡣࠊ_α-R2S3ࡢ↓☢ ሙୗ࠾ࡼࡧ☢ሙ୰࡛ࡢẚ⇕ࡢ ᐃ⤖ᯝ࡜⵳෭ᮦ࣭ ☢Ẽ෭෾ᮦ࡜ࡋ࡚ࡢྍ⬟ᛶ࡟ࡘ࠸࡚㆟ㄽࡍࡿࠋ 3 ᐇ㦂  ᕷ㈍ࡢᕼᅵ㢮㓟໬≀ࢆ _CS2Ẽὶ୰࡛ຍ⇕ࡍࡿࡇ ࡜࡛ α-R2S3⢊ᮎヨᩱࢆᚓࠊࡇࢀࢆཎᩱ࡜ࡋ࡚ࣚ࢘ ⣲ࢆ㍺㏦๣࡜ࡋࡓẼ┦໬Ꮫ㍺㏦ἲ࡟ࡼࡾ༢⤖ᬗヨ ᩱࢆ⫱ᡂࡋࡓࠋẚ⇕ࡣ⡿ᅜQuantum Design ♫〇≀ ⌮≉ᛶ ᐃࢩࢫࢸ࣒ _{PPMS ࢆ౑⏝ࡋࠊ5 T ࡲ࡛ࡢ} ✀ࠎࡢ☢ሙ୰࡛⦆࿴ἲ࡟ࡼࡾ ᐃࡋࡓࠋ 4 ⤖ᯝ࡜⪃ᐹ 4.1 ↓☢ሙୗẚ⇕  ᅗ_{1 ࡟ α-R}2S3䠄R㸸Pr, Nd, Sm, Gd, Tb, Dy䠅༢⤖ᬗ ࡢ↓☢ሙୗ࡛ࡢẚ⇕ࡢ ᗘ౫Ꮡᛶࢆ♧ࡍࠋ_{Gd, Pr} ⣔௨እࡢ α-R2S3࡛ࡣ㸰ẁࡢ☢Ẽ┦㌿⛣࡟క࠺ඛ㗦 ࡞ࣆ࣮ࢡࡀ☜ㄆࡉࢀࡿࠋ_{Tb, Dy ⣔࡟㛵ࡋ࡚ࡣ☢໬}  ᐃ(12)(14)_{ࡸ୰ᛶᏊᅇᢡᐇ㦂}(19)_{ࡢ⤖ᯝ࠿ࡽࠊ㸰ẁࡢ} ཯ᙉ☢ᛶ㌿⛣ࡀ㉳ࡁ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿࠋ_{Nd ⣔ࡢ} ᑡ࡞ࡃ࡜ࡶ㧗 ഃࣆ࣮ࢡࡣࡸࡣࡾ཯ᙉ☢ᛶ㌿⛣࡟ ࡼࡿࡶࡢ࡛࠶ࡿࠋࡇࢀ࡟ᑐࡋ࡚_{Sm ⣔࡛ࡢ㌿⛣ࡣ㸰} ẁࡢ䠄ᙅ䠅ᙉ☢ᛶ㌿⛣࡛࠶ࡿ࡜⪃࠼ࡽࢀࡿ(16)_{ࠋPr ⣔} ࡛ࡣ᭱ప ࡢ_{0.36 K ࡲ࡛➨஧ࡢࣆ࣮ࢡࡣ☜ㄆࡉࢀ} ࡞࠸ࡶࡢࡢࠊప ࡛ࡢ᫂ࡽ࠿࡞ẚ⇕ࡢୖ᪼࠿ࡽ㏲ ḟⓗ┦㌿⛣ࡀ࠶ࡿ࡜⪃࠼ࡽࢀࡿࠋ_α-Tb2S3࡛ࡢ☢Ẽ ᵓ㐀ゎᯒ⤖ᯝ(19)_{࡜௚ࡢᐇ㦂஦ᐇ࠿ࡽࠊࡇࢀࡽࡢ㧗}  ഃ㌿⛣࡛ࡣ _{R1ࠊప ഃ㌿⛣࡛ࡣ R2 ࡀ⛛ᗎ໬ࡍ} ᡁ ಟ஧㸪㜿Ἴຍ ῟஧㸪⸨ ⪔୍㑻

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ࡁ࡞඲ゅ㐠ື㔞㔞Ꮚᩘࢆࡶࡘ㔜ᕼᅵ㢮ඖ⣲ࢆྵࡴ ≀㉁ࡀೃ⿵࡜࡞ࡾᚓࡿࠋ_{10 K ⛬ᗘ࡛☢Ẽ┦㌿⛣ࢆ} ࡶࡘα ኚែᕼᅵ㢮୕஧◲໬≀ α-R2S3䠄R㸸ᕼᅵ㢮ඖ ⣲䠅ࡸᕼᅵ㢮࣍࢘໬≀࡟╔┠ࡋࠊ⣔⤫ⓗ࡞ẚ⇕ ᐃ ࢆ⾜ࡗࡓࠋ  ☢Ẽ෭෾ᮦ࡟㛵ࡋ࡚ࡣືస ᗘࢆ⪃៖ࡍࡿࡇ࡜ ࡀ㔜せ࡛࠶ࡾࠊᮏࢱࢫࢡ࣓ࣥࣂ࣮ࡀࡶࡘࢩ࣮ࢬࢆ ㋃ࡲ࠼ࠊ_{(1)ᐊ ᇦࠊ(2)ᾮయ❅⣲ ᗘᇦࠊ(3)10 K} ᗘᇦ࡛ࡢ᳨ウࢆ⾜ࡗࡓࠋ  _{(1)ᐊ ᇦ㸸ᐊ ᇦ࡟࠾ࡅࡿ☢Ẽ෭෾ᶵࡣࠊࣇࣟ} ࣥ࢞ࢫ࡟ࡼࡿ࢜ࢰࣥᒙࡢ◚ቯࠊ௦᭰ࣇࣟࣥ࢞ࢫ࡟ ࡼࡿᆅ⌫ ᬮ໬ࡢಁ㐍ࢆ㜼ࡴࡶࡢ࡜ࡋ࡚ᮇᚅࡉࢀ ࡚࠸ࡿࠋࡇࡢ ᗘᇦ࡟࠾࠸࡚ࡣࠊᐊ ௜㏆࡟ᙉ☢ ᛶ㌿⛣ ᗘ䠄࣮࢟ࣗࣜⅬ䠅_TC ࢆࡶࡘᕼᅵ㢮ඖ⣲ _Gd ࡀึᮇࡢ㡭ࡼࡾὀ┠ࡉࢀ࡚ᐇᶵ࡛ࡶホ౯ࡉࢀࠊᐊ  ☢Ẽ෭෾ࢩࢫࢸ࣒ࡢⓎᒎ࡟኱ࡁ࡞ᙺ๭ࢆᢸࡗ࡚ ࡁࡓࠋ㧗ຠ⋡࣭㧗ᛶ⬟໬ࡢࡓࡵ࡟✀ࠎࡢGd ໬ྜ≀ࠊ ౛࠼ࡤ_Gd5Si2Ge2(1)(2)_{ࡸࠊ㠀☢ᛶࡢᕼᅵ㢮ඖ⣲La ࢆ} ྵࡴ La(Fe1-xSix)13Hy(3)(4)࠶ࡿ࠸ࡣᕼᅵ㢮ඖ⣲ࢆྵࡲ ࡞࠸_Mn(As1-xSbx)(5)ࡸ MnFe(P1-xAsx)(6)࡞࡝ࡀὀ┠ࢆ 㞟ࡵ࡚┒ࢇ࡟◊✲ࡉࢀࠊᐇ⏝໬࡟㏆࡙࠸࡚࠸ࡿࠋ ᕼᅵ㢮ඖ⣲ࢆ⏝࠸ࡎ࡜ࡶࠊ୍ḟ┦㌿⛣ࡢ኱ࡁ࡞࢚ ࣥࢺࣟࣆ࣮ኚ໬ࢆ฼⏝ࡍࢀࡤ㧗ᛶ⬟ࡢ෭෾ᶵࢆᐇ ⌧࡛ࡁࡿྍ⬟ᛶࡀ♧ࡉࢀࠊ⌧ᅾࡢ୍ࡘࡢ₻ὶ࡜࡞ ࡾࡘࡘ࠶ࡿࠋᚋⓎࡢᮏࢱࢫࢡ࡛ࡣࠊ⌧᭷ࡢࢩ࣮ࢬ ࡛࠶ࡿᐊ ᇦ࡛␗ᖖ࡟኱ࡁ࡞⇕⭾ᙇ⋡䠄ẚ⇕࡜ᐦ ᥋࡟㛵㐃ࡍࡿ≀⌮㔞䠅ࢆ♧ࡍᕼᅵ㢮ඖ⣲ Ce ࢆྵࡴ ᵓ㐀୙つ๎⣔ྜ㔠(7)-(9)_{ࡢᇶ♏◊✲ࢆ㐍ࡵࡓࠋ}  (2)ᾮయ❅⣲ ᗘᇦ㸸㖡㓟໬≀㧗 ㉸ఏᑟయࢆ⏝ ࠸ࡓ✀ࠎࡢࢹࣂ࢖ࢫࡀ฼⏝ࡉࢀ࡚ࡁ࡚࠸ࡿࡀࠊࡇ ࡢᏳ ᐃືసࡢ ࡓࡵ࡟ࡣ ᾮయ❅ ⣲ ᗘ 䠄❅⣲ࡢ Ἓ Ⅼ㸸_{77 K䠅ࡼࡾᩘ༑ K ప࠸ ᗘࡀᚲせ࡛࠶ࡾࠊࡇࢀ} ࢆᐇ⌧ࡍࡿపࢥࢫࢺ࣭ప᣺ື࣭ప㦁㡢ࡢᑠᆺ☢Ẽ ෭෾ᶵࡀᮃࡲࢀࡿࠋࡑࡢᙧᡂࣃࢱ࣮ࣥ࠿ࡽࢫࢺࣛ ࢖ࣉ⛛ᗎ࡜࿧ࡤࢀࡿ㟁Ⲵ⛛ᗎࢆ㉸ఏᑟ㌿⛣࡟కࡗ ࡚㉳ࡇࡍ㖡㓟໬≀㧗 ㉸ఏᑟయ࡟㛵ࡍࡿ◊✲ࢩ࣮ ࢬ(10)ࡀ࠶ࡾࠊࡇࡢ㌿⛣࡟క࠺࢚ࣥࢺࣟࣆ࣮ኚ໬ࢆ ྵࡵࡓᇶ♏◊✲࡟ྲྀࡾ⤌ࢇࡔࠋ  (3)10 K  ᗘᇦ㸸ࢡ࣮࢚ࣜࣥࢿࣝࢠ࣮࡜ࡋ࡚ᮇᚅ ࡉࢀࡿỈ⣲⇞ᩱࢆ㈓ⶶ࣭㍺㏦ࡍࡿࡓࡵ࡟ࡣỈ⣲ࢆ ᾮ໬ࡍࡿࡢࡀຠ⋡ⓗ࡛࠶ࡾࠊ10 K ⛬ᗘࡢ ᗘࢆᐇ ⌧ࡍࡿᚲせࡀ࠶ࡿࠋᾮయ࣒࣊ࣜ࢘ࢆ౑⏝ࡍࢀࡤࠊ ᾐₕࡍࡿࡔࡅ࡛࣒࣊ࣜ࢘ࡢἛⅬ 4.2 K ㏆ࡃࡲ࡛෭ ༷ࡍࡿࡇ࡜ࡀྍ⬟࡛࠶ࡿࡀࠊ࣒࣊ࣜ࢘ࡣᕼᑡ㈨※ ࡛࠶ࡾࠊ♫఍᝟ໃ࡟ࡼࡗ࡚ࡣ☜ಖࡀࡁࢃࡵ࡚ᅔ㞴 ࡟ࡶ࡞ࡾᚓࡿࠋࡇࡢࡓࡵࠊ࣒࣊ࣜ࢘ࣇ࣮࡛ࣜྠ➼ ࡢ ᗘࢆᚓࡿᑠᆺ࣭పࢥࢫࢺ࣭ప᣺ື࣭ప㦁㡢ࡢ ☢Ẽ෭෾ᶵࡢ㛤Ⓨࡀᮇᚅࡉࢀ࡚࠸ࡿࠋࡇࢀࡲ࡛ⴭ ⪅ࡣ๓㏙ࡢα-R2S3ࡀ10 K ௜㏆ࡢ ᗘ࡛㏲ḟ☢Ẽ┦ ㌿⛣ࢆ㉳ࡇࡋࠊࡑࢀ࡟కࡗ࡚✀ࠎࡢ≉␗࡞≀ᛶᛂ ⟅ࢆ♧ࡍࡇ࡜ࢆぢฟࡋ࡚ࡁࡓ(11)-(18)ࠋࡇࡢ◊✲ࢩ࣮ ࢬࢆά࠿ࡋࠊ_α-R2S3ࡢ☢Ẽ෭෾ᮦ࡜ࡋ࡚ࡢྍ⬟ᛶࢆ ᥈ࡗࡓࠋ  _α-R2S3ࡣᩳ᪉ᬗ⣔⤖ᬗᵓ㐀䠄✵㛫⩌㸸_{Pnma䠅୰࡟} ⤖ᬗᏛⓗ࡟⊂❧࡞஧ࡘࡢᕼᅵ㢮ࢧ࢖ࢺ㸦R1, R2㸧ࢆ ᭷ࡋ࡚࠸ࡿ(11)_{ࠋࡇࢀࡲ࡛࡟ᚓࡽࢀࡓᐇ㦂஦ᐇࢆ⥲} ᣓࡍࡿ࡜ࠊR1 ࡣ b ㍈᪉ྥ୍ḟඖ㙐ෆ࡛ᙉ☢ᛶⓗࠊa ㍈᪉ྥࢪࢢࢨࢢ㙐ෆ࡛཯ᙉ☢ᛶⓗ࡟⛛ᗎ໬ࡍࡿഴ ྥࡀᙉࡃࠊR1 ࡜ᙅࡃ⤖ྜࡋࡓ R2 ࡣ㊥㞳ⓗ࡟ࡣࡸ ࡸ㐲࠸㞄᥋ _{R2 ࡜」㞧࡟స⏝ࡋྜ࠺࡜⪃ᐹࡉࢀࡿࠋ} ࡇࡢR1-R2, R2-R2 㛫ࡢ」㞧࡞☢Ẽⓗ┦஫స⏝ࡀ➇ ྜࡋࠊ ᗘࡸ☢ሙ࡟ᑐࡋ࡚࣐ࢡࣟ≀ᛶࡀ≉␗࡞ᛂ ⟅ࢆ♧ࡍ࡜⪃࠼ࡽࢀࡿࠋᮏሗ࿌࡛ࡣࠊα-R2S3ࡢ↓☢ ሙୗ࠾ࡼࡧ☢ሙ୰࡛ࡢẚ⇕ࡢ ᐃ⤖ᯝ࡜⵳෭ᮦ࣭ ☢Ẽ෭෾ᮦ࡜ࡋ࡚ࡢྍ⬟ᛶ࡟ࡘ࠸࡚㆟ㄽࡍࡿࠋ 3 ᐇ㦂  ᕷ㈍ࡢᕼᅵ㢮㓟໬≀ࢆ _CS2Ẽὶ୰࡛ຍ⇕ࡍࡿࡇ ࡜࡛ α-R2S3⢊ᮎヨᩱࢆᚓࠊࡇࢀࢆཎᩱ࡜ࡋ࡚ࣚ࢘ ⣲ࢆ㍺㏦๣࡜ࡋࡓẼ┦໬Ꮫ㍺㏦ἲ࡟ࡼࡾ༢⤖ᬗヨ ᩱࢆ⫱ᡂࡋࡓࠋẚ⇕ࡣ⡿ᅜ_{Quantum Design ♫〇≀} ⌮≉ᛶ ᐃࢩࢫࢸ࣒ _{PPMS ࢆ౑⏝ࡋࠊ5 T ࡲ࡛ࡢ} ✀ࠎࡢ☢ሙ୰࡛⦆࿴ἲ࡟ࡼࡾ ᐃࡋࡓࠋ 4 ⤖ᯝ࡜⪃ᐹ 4.1 ↓☢ሙୗẚ⇕  ᅗ_{1 ࡟ α-R2S3}䠄_{R㸸Pr, Nd, Sm, Gd, Tb, Dy䠅༢⤖ᬗ} ࡢ↓☢ሙୗ࡛ࡢẚ⇕ࡢ ᗘ౫Ꮡᛶࢆ♧ࡍࠋGd, Pr ⣔௨እࡢ _α-R2S3࡛ࡣ㸰ẁࡢ☢Ẽ┦㌿⛣࡟క࠺ඛ㗦 ࡞ࣆ࣮ࢡࡀ☜ㄆࡉࢀࡿࠋTb, Dy ⣔࡟㛵ࡋ࡚ࡣ☢໬  ᐃ(12)(14)_{ࡸ୰ᛶᏊᅇᢡᐇ㦂}(19)_{ࡢ⤖ᯝ࠿ࡽࠊ㸰ẁࡢ} ཯ᙉ☢ᛶ㌿⛣ࡀ㉳ࡁ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿࠋNd ⣔ࡢ ᑡ࡞ࡃ࡜ࡶ㧗 ഃࣆ࣮ࢡࡣࡸࡣࡾ཯ᙉ☢ᛶ㌿⛣࡟ ࡼࡿࡶࡢ࡛࠶ࡿࠋࡇࢀ࡟ᑐࡋ࡚Sm ⣔࡛ࡢ㌿⛣ࡣ㸰 ẁࡢ䠄ᙅ䠅ᙉ☢ᛶ㌿⛣࡛࠶ࡿ࡜⪃࠼ࡽࢀࡿ(16)_{ࠋPr ⣔} ࡛ࡣ᭱ప ࡢ0.36 K ࡲ࡛➨஧ࡢࣆ࣮ࢡࡣ☜ㄆࡉࢀ ࡞࠸ࡶࡢࡢࠊప ࡛ࡢ᫂ࡽ࠿࡞ẚ⇕ࡢୖ᪼࠿ࡽ㏲ ḟⓗ┦㌿⛣ࡀ࠶ࡿ࡜⪃࠼ࡽࢀࡿࠋα-Tb2S3࡛ࡢ☢Ẽ ᵓ㐀ゎᯒ⤖ᯝ(19)_{࡜௚ࡢᐇ㦂஦ᐇ࠿ࡽࠊࡇࢀࡽࡢ㧗}  ഃ㌿⛣࡛ࡣ R1ࠊప ഃ㌿⛣࡛ࡣ R2 ࡀ⛛ᗎ໬ࡍ 㧗ᛶ⬟☢Ẽ⇕ኚ᥮ᮦᩱࡢ㛤Ⓨࢆ┠ᣦࡋ࡚

- 35 -

ࡿ࡜㢮᥎ࡉࢀࡿࠋ୍᪉࡛୰ᛶᏊᅇᢡᐇ㦂(20)ࡸ࢚ࣥ ࢺࣟࣆ࣮ኚ໬(21)_{࠿ࡽ☜ㄆࡉࢀࡿࡼ࠺࡟ࠊα-Gd2S3ࡣ} 㸯ẁࡢ㌿⛣࡛Gd1, Gd2 ࡀ཯ᙉ☢ᛶ⛛ᗎ໬ࡍࡿࠋ 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0 5 10 15 20

C

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m

-3

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R

2

S

3 R = Gd Tb Dy Pr Nd Sm ᅗ_{1 α-R2S3}༢⤖ᬗࡢẚ⇕ࡢ ᗘ౫Ꮡᛶ  ᅗ_{1 ࠿ࡽ᫂ࡽ࠿࡞ࡼ࠺࡟ࠊα-Gd2S3}ࡢẚ⇕ࣆ࣮ࢡ ࡣ௚ࢆᅽಽࡋ࡚኱ࡁ࠸ࠋከ㔜㡯ᇶᗏ≧ែ࡟࠾࠸࡚ Gd3+_{ࡢ඲ゅ㐠ື㔞J ࡣ 7/2 ࡜ẚ㍑ⓗ኱ࡁ࠸ࡀࠊTb}3+ (J = 6)ࡸ Dy3+ _{(J = 15/2)ࡢ᪉ࡀࡉࡽ࡟኱ࡁ࠸ࠋࡋ࠿ࡋࠊ} Gd ⣔௨እࡢ J ከ㔜㡯ࡣ⤖ᬗሙ࡟ࡼࡗ࡚࢚ࢿࣝࢠ࣮ ‽఩ศ⿣ࡋࠊᇶᗏ㡯ࡢከ㔜ᗘࡣపࡃ࡞ࡿࠋ୍᪉_Gd ⣔࡛ࡣ㌶㐨ゅ㐠ື㔞ࡀ _{0 ࡛࠶ࡿࡓࡵ࡟⤖ᬗሙࡢᙳ} 㡪ࢆཷࡅࡎࠊᇶᗏࡀࢫࣆࣥ _{8 㔜㡯࡛࠶ࡿࡇ࡜࡟㉳} ᅉࡋ࡚ẚ⇕ࣆ࣮ࢡࡀ኱ࡁࡃ࡞ࡗ࡚࠸ࡿࠋࡉࡽ࡟_Gd ⣔࡛ࡣ㌿⛣ࡼࡾప ࡛ẚ⇕ࡀ⫪ࢆࡶࡗ࡚࠸ࡿࠋࡇ ࢀࡣᗄఱᏛⓗࣇࣛࢫࢺ࣮ࣞࢩࣙࣥࢆ᭷ࡍࡿ_{Gd2 ࡢ} ⛛ᗎ໬ࡀ_{Gd1 ࡢ⮬Ⓨ⛛ᗎ࡟ࡼࡿศᏊሙࡢᙳ㡪࡛ࠊ}  ᗘపୗ࡟కࡗ࡚ᚎࠎ࡟㐍⾜ࡋ࡚࠸ࡿࡇ࡜࡟㉳ᅉ ࡋ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿ(21)_{ࠋࡇࡢࡓࡵࠊα-Gd2S3ࡣᗈ} ࠸ ᗘ⠊ᅖ࡛኱ࡁ࡞ẚ⇕ࢆࡶࡘࠋ༢఩య✚࠶ࡓࡾ ࡢẚ⇕ࡢ᭱኱್_{0.63 J K}-1_cm-3 _{(T = 9.8 K)ࡣ⵳෭ᮦ} ࡜ ࡋ ࡚ ᮇ ᚅ ࡉ ࢀ ࡚ ࠸ ࡿ _{Gd2O2S (GOS) ࡢ 1.1} J K-1_cm-3 _{(T = 5.2 K)ࡼࡾࡶప࠸ࡀࠊᐇ⏝໬ࡉࢀ࡚࠸} ࡿ_{Er3Ni ࡸ HoCu2}ࢆ෽㥙ࡋ࡚࠸ࡿࠋ_HoCu2ࡀࢲࣈࣝ ࣆ࣮ࢡ࡛ࡼ࠸ᛶ⬟ࢆ♧ࡍ ᗘᇦ࡛ࡣ್ࡀୗᅇࡿࡀ α-Gd2S3ࡢᖜᗈࡢ⫪ࡣⰋ࠸≉ᚩ࡛࠶ࡿࠋࡲࡓࠊࡼࡾ ኱ࡁ࡞ẚ⇕ࣆ࣮ࢡࢆࡶࡘᙉ☢ᛶయ _{ErNi ࡛ࡣ࡞ࡃ} Er3Ni ࡀᐇ⏝໬ࡉࢀ࡚࠸ࡿ⌮⏤ࡣᚋ⪅ࡀ཯ᙉ☢ᛶయ ࡛࠶ࡾ㉸ఏᑟ࣐ࢢࢿࢵࢺ࠿ࡽࡢ₃ࢀ☢ሙࡢᙳ㡪ࢆ ཷࡅ࡟ࡃ࠸ࡓࡵ࡛࠶ࡿࡀࠊࡑࡢⅬ࡛ࡶ཯ᙉ☢ᛶయ α-Gd2S3ࡣ㐺ࡋ࡚࠸ࡿࠋ኱ࡁ࡞ẚ⇕ࢆ♧ࡍ ᗘᇦࡀ ␗࡞ࡿ⵳෭ᮦࢆ⤌ࡳྜࢃࡏ࡚෭෾ᶵ➼࡟඘ሸࡍࡿ ࡇ࡜࡟ࡼࡾ㧗ຠ⋡໬ࡀᅗࢀࡿࡓࡵࠊࢲࣈࣝࣆ࣮ࢡ ࢆ♧ࡍ௚ࡢ α-R2S3ࡶྵࡵࠊẚ⇕≉ᛶⓗ࡟ࡣ⵳෭ᮦ ࡜ࡋ࡚ࡢྍ⬟ᛶࡣ࠶ࡿࠋࡋ࠿ࡋᐇᮦᩱ࡜ࡋ࡚ࡣࠊ ⌫≧ከ⤖ᬗヨᩱࡢసᡂྍ⬟ᛶࠊࡑࡢሙྜࡢẚ⇕≉ ᛶࡸ⇕ఏᑟ⋡ࠊ⇕ࢧ࢖ࢡࣝࢆྵࡵࡓ⪏⎔ቃᛶࠊࢥ ࢫࢺ➼ࡢ᳨ウࡍ࡭ࡁㄢ㢟ࡣᩘከࡃᏑᅾࡍࡿࠋ 4.2 ☢ሙ୰ẚ⇕  ᅗ2 ࡟ α-Dy2S3ࡢb ㍈࡟ᑐࡋ࡚ᆶ┤࡟☢ሙࢆ༳ຍ ࡋࡓሙྜࡢ_{(a)☢Ẽẚ⇕ Cm}࠾ࡼࡧ_{(b)☢Ẽ࢚ࣥࢺࣟ} ࣆ࣮Smࡢ ᗘ౫Ꮡᛶࢆ♧ࡍࠋ㧗 ഃ㌿⛣ⅬTN1ࡀ☢ ሙ༳ຍ࡟ࡼࡾ㢧ⴭ࡟㧗 ഃ࡟ࢩࣇࢺࡋࠊప ഃ㌿ ⛣ࡀᾘኻࡋ࡚࠸ࡿᵝᏊࡀࢃ࠿ࡿࠋᙉ☢ᛶ㌿⛣ࡀ☢ ሙ༳ຍ࡟ࡼࡾ㧗 ഃ࡟ࢩࣇࢺࡍࡿࡇ࡜ࡣࡼࡃぢࡽ ࢀࡿࡇ࡜࡛ࠊࡇࡢഴྥࡣ☢Ẽ෭෾࡟࡜ࡗ࡚ࡣ㒔ྜ ࡀⰋ࠸ࠋࡋ࠿ࡋࠊ཯ᙉ☢ᛶ㌿⛣ࡣ☢ሙ༳ຍ࡟ࡼࡾ ప ഃ࡟ࢩࣇࢺࡍࡿࡢࡀ୍⯡ⓗ࡛࠶ࡿࠋ⌧࡟௚ࡢ α-R2S3࡛ࡣ☢ሙࡢ༳ຍ᪉ྥ࡟ࡼࡽࡎ㌿⛣ࡢప ࢩ ࣇࢺࡀほ ࡉࢀࡿࡋࠊα-Dy2S3ࡢb ㍈࡟ᖹ⾜࡞☢ሙ ༳ຍ࡛ࡶྠᵝࡢഴྥࡀぢࡽࢀࡿࠋ_α-Dy2S3ࡣ㏲ḟ཯ ᙉ☢ᛶ㌿⛣Ⅼࡢ㛫TN1-TN2࡛✀ࠎࡢ≉␗࡞⌧㇟ࢆ♧ ࡍ(13)(14)_{ࡀࠊb ㍈࡟ᆶ┤࡞☢ሙ࡟ᑐࡍࡿᛂ⟅ࡀ㗦ᩄ} ࡛࠶ࡿࡇ࡜ࡶࡑࡢ୍ࡘ࡛࠶ࡿࠋDy1 ࡀ཯ᙉ☢ᛶ⛛ ᗎ໬ࡍࡿࡇ࡜࡟ࡼࡾࠊ_{Dy2 ࡢ☢ሙ࡟ᑐࡍࡿᛂ⟅ᛶ} ࡀࡼࡃ࡞ࡾࠊ☢ሙ࡟ࡼࡿࢮ࣮࣐࢚ࣥࢿࣝࢠ࣮పୗ ࡀ࠶ࡿࡓࡵ࡟ࠊ_TN1ࡀ㧗 ࢩࣇࢺࡍࡿ࡜⪃࠼ࡽࢀࡿࠋ 0 10 20 30 40 50

-

Dy₂

S

₃

C

m

/ J

K

-1

mol

-1

Hԋb

0 T 1 T2 T 3 T 5 T

(a)

0 5 10 15 20 0 5 10 15 20

-

Dy₂

S

₃

S

m

/ J

K

-1

mol

-1

Hԋb

0 T1 T 2 T 5 T 3 T

(b)

T / K

ᅗ_{2 α-R}2S3༢⤖ᬗࡢ☢ሙ୰࡛ࡢ(a)☢Ẽẚ⇕࡜ (b)☢Ẽ࢚ࣥࢺࣟࣆ࣮ࡢ ᗘ౫Ꮡᛶ  _TN1ࡢ㧗 ࢩࣇࢺ࡜ప ഃ_TN2࡛ࡢ㌿⛣ࡢᾘኻࡀ ࡜ࡶ࡟ຠ࠸࡚ࠊᅗ_{2(b)࡟♧ࡍࡼ࠺࡟ C}m/T ࢆ ᐃ᭱ ప ᗘ _{0.4 K ࠿ࡽ ᗘ࡛✚ศࡋࡓ☢Ẽ࢚ࣥࢺࣟࣆ} ࣮ࡣ☢ሙ༳ຍ࡟ࡼࡾῶᑡࡋ࡚࠸ࡿ㸦_|Sm| < 0㸧ࠋບ ☢࡟Ọஂ☢▼ࡢ฼⏝ࢆ᝿ᐃࡋࡓ☢ሙ _{2 T ࡛ࡢ|Sm|}

α

α

－　36　－ ᡁ ಟ஧㸪㜿Ἴຍ ῟஧㸪⸨ ⪔୍㑻

- 36 -

ࡣᑠࡉ࠸ࡀࠊ㉸ఏᑟ࣐ࢢࢿࢵࢺࡢ฼⏝ࢆ᝿ᐃࡋࡓ₅ T ࡛ࡣ኱ࡁ࡞|Sm|ࡀ☜ㄆࡉࢀࡿࠋ12 K ࡢ➼ ≧ែ ࡛_{5 T ࡢ☢ሙࢆ༳ຍࡋࠊ᩿⇕≧ែ࡛ᾘ☢ࡋࡓሙྜࡢ}  ᗘῶᑡࡣࠊᅗ_2(b)࠿ࡽTad= 5.8 K ࡜ぢ✚ࡶࡽࢀ ࡿࠋ☢Ẽ෭෾ᮦ࡜ࡋ࡚᥋ࡍࡿ≀㉁࠿ࡽ⇕ࢆዣ࠺ࡓ ࡵ࡟ࡣࠊ༢఩య✚࠶ࡓࡾࡢ࢚ࣥࢺࣟࣆ࣮ῶᑡࡀ኱ ࡁ࠸ᚲせࡀ࠶ࡿࡀࠊᮏ⣔ࡣ_Dy2S3࡜࠸࠺໬Ꮫᘧ࠿ࡽ ࢃ࠿ࡿࡼ࠺࡟ᕼᅵ㢮ᐦᗘࡀప࠸ศ୙฼࡛࠶ࡿࠋࡋ ࠿ࡋࠊ_α-R2S3ࡢእሙ࡟ᑐࡍࡿ≉␗࡞≀ᛶᛂ⟅ࢆ฼⏝ ࡋࠊ☢Ẽ⇕㔞ຠᯝࢆไᚚࡋᚓࢀࡤࠊእሙไᚚ࡜࠸ ࠺௜ຍ౯್ࢆࡶࡗࡓ☢Ẽ෭෾ᮦࡀᐇ⌧ࡋᚓࡿࡢ࡛ ࡣ࡞࠸࠿࡜࠸࠺ほⅬ࡛ᇶ♏≀ᛶ◊✲ࢆ㐍ࡵ࡚࠸ࡿࠋ 5 ࡲ࡜ࡵ  ᕼᅵ㢮◲໬≀ α-R2S3༢⤖ᬗࡢ↓☢ሙୗ࠾ࡼࡧ☢ ሙ୰ẚ⇕ࢆ ᐃࡋࠊ_α-Gd2S3ࡢ⵳෭ᮦ࡜ࡋ࡚ࡢྍ⬟ ᛶࠊα-Dy2S3ࡢ☢Ẽ෭෾ᮦ࡜ࡋ࡚ࡢྍ⬟ᛶࢆぢฟࡋ ࡓࠋࡋ࠿ࡋᐇᮦᩱ࡜ࡋ࡚ࡢඃ఩ᛶ࡟ࡘ࠸࡚ࡣࠊከ ࡃࡢ᳨ウࡍ࡭ࡁㄢ㢟ࡀṧࡉࢀ࡚࠸ࡿࠋα-R2S3ࡢ☢Ẽ ⇕㔞ຠᯝࢆእሙไᚚࡍࡿྍ⬟ᛶ࡟ࡘ࠸࡚ࡶࠊ௒ᚋ ࡉࡽ࡟᳨ウࡋ࡚࠸ࡃࠋ ㅰ㎡  ᮏ◊✲ࡢ୍㒊ࡣ_{JSPS ⛉◊㈝ 23540384 ࡢຓᡂࢆ} ཷࡅ࡚࡞ࡉࢀࡲࡋࡓࠋ ཧ⪃ᩥ⊩

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Jpn., 73 (2004) p2955-2958. ᡁ ಟ஧㸪㜿Ἴຍ ῟஧㸪⸨ ⪔୍㑻

- 36 -

ࡣᑠࡉ࠸ࡀࠊ㉸ఏᑟ࣐ࢢࢿࢵࢺࡢ฼⏝ࢆ᝿ᐃࡋࡓ5 T ࡛ࡣ኱ࡁ࡞|Sm|ࡀ☜ㄆࡉࢀࡿࠋ12 K ࡢ➼ ≧ែ ࡛5 T ࡢ☢ሙࢆ༳ຍࡋࠊ᩿⇕≧ែ࡛ᾘ☢ࡋࡓሙྜࡢ  ᗘῶᑡࡣࠊᅗ_{2(b)࠿ࡽTad= 5.8 K ࡜ぢ✚ࡶࡽࢀ} ࡿࠋ☢Ẽ෭෾ᮦ࡜ࡋ࡚᥋ࡍࡿ≀㉁࠿ࡽ⇕ࢆዣ࠺ࡓ ࡵ࡟ࡣࠊ༢఩య✚࠶ࡓࡾࡢ࢚ࣥࢺࣟࣆ࣮ῶᑡࡀ኱ ࡁ࠸ᚲせࡀ࠶ࡿࡀࠊᮏ⣔ࡣDy2S3࡜࠸࠺໬Ꮫᘧ࠿ࡽ ࢃ࠿ࡿࡼ࠺࡟ᕼᅵ㢮ᐦᗘࡀప࠸ศ୙฼࡛࠶ࡿࠋࡋ ࠿ࡋࠊα-R2S3ࡢእሙ࡟ᑐࡍࡿ≉␗࡞≀ᛶᛂ⟅ࢆ฼⏝ ࡋࠊ☢Ẽ⇕㔞ຠᯝࢆไᚚࡋᚓࢀࡤࠊእሙไᚚ࡜࠸ ࠺௜ຍ౯್ࢆࡶࡗࡓ☢Ẽ෭෾ᮦࡀᐇ⌧ࡋᚓࡿࡢ࡛ ࡣ࡞࠸࠿࡜࠸࠺ほⅬ࡛ᇶ♏≀ᛶ◊✲ࢆ㐍ࡵ࡚࠸ࡿࠋ 5 ࡲ࡜ࡵ  ᕼᅵ㢮◲໬≀ α-R2S3༢⤖ᬗࡢ↓☢ሙୗ࠾ࡼࡧ☢ ሙ୰ẚ⇕ࢆ ᐃࡋࠊ_α-Gd2S3ࡢ⵳෭ᮦ࡜ࡋ࡚ࡢྍ⬟ ᛶࠊα-Dy2S3ࡢ☢Ẽ෭෾ᮦ࡜ࡋ࡚ࡢྍ⬟ᛶࢆぢฟࡋ ࡓࠋࡋ࠿ࡋᐇᮦᩱ࡜ࡋ࡚ࡢඃ఩ᛶ࡟ࡘ࠸࡚ࡣࠊከ ࡃࡢ᳨ウࡍ࡭ࡁㄢ㢟ࡀṧࡉࢀ࡚࠸ࡿࠋα-R2S3ࡢ☢Ẽ ⇕㔞ຠᯝࢆእሙไᚚࡍࡿྍ⬟ᛶ࡟ࡘ࠸࡚ࡶࠊ௒ᚋ ࡉࡽ࡟᳨ウࡋ࡚࠸ࡃࠋ ㅰ㎡  ᮏ◊✲ࡢ୍㒊ࡣJSPS ⛉◊㈝ 23540384 ࡢຓᡂࢆ ཷࡅ࡚࡞ࡉࢀࡲࡋࡓࠋ ཧ⪃ᩥ⊩

(1) V. K. Pecharsky and K. A. Gschneidner, Jr., Giant Magnetocaloric Effect in Gd5(Si2Ge2), Phys. Rev. Lett.,

76 (1997) p4494-4497.

(2) V. K. Pecharsky and K. A. Gschneidner, Jr., Tunable magnetic regenerator alloys with a giant magnetocaloric effect for magnetic refrigeration from ~20 to ~290̴K, Appl. Phys. Lett., 70 (1997) p3299-3301.

(3) A. Fujita, S. Fujieda, Y. Hasegawa, and K. Fukamichi, Itinerant-electron metamagnetic transition and large magnetocaloric effects in La(FexSi1-x)13 compounds and

their hydrides, Phys. Rev. B, 67 (2003) 104416(12 pages).

(4) A. Fujita, S. Fujieda, K. Fukamichi, Y. Yamazaki, and Y. Iijima, Giant Magnetic Entropy Change in Hydrogenated La(Fe0.88Si0.12)13Hy Compounds, Mater. Trans., 43 (2002)

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ᐊᕤ኱⣖せ➨63 ྕ㸦2013㸧 37㹼40

- 37 -

ᵓ㐀౫Ꮡᕼᅵ㢮ྜ㔠ࡢ㛤Ⓨ࡜☢Ẽ⇕㔞࣭⇕ᙎᛶᮦᩱ࡬ࡢᒎ㛤

㞵ᾏ

᭷భ

*1, *2

_㸪ሷᑼ

_Ὀᗈ

*3

_㸪㕥ᮌ

_ᣅஓ

*3

_㸪▼ཎ

_ᆂ

*3

_㸪ᮧᒣ

_ⱱᖾ

*1, *2

Development of Magnetocaloric and Thermoelastic Materials in

Structure-dependent Rare-earth Alloys

Yusuke AMAKAI

*1, *2

_{, Yasuhiro SHIOJIRI}

*3

_{, Takuya SUZUKI}

*3

Kei ISHIHARA

*3

_{, and Shigeyuki MURAYAMA}

*1, *2

㸦ཎ✏ཷ௜᪥ ᖹᡂ

_{25 ᖺ 9 ᭶ 30 ᪥ ㄽᩥཷ⌮᪥ ᖹᡂ 26 ᖺ 1 ᭶ 24 ᪥㸧}

Abstract

This study aims to develop next-generation high-performance materials with utilizing the strongly correlated electronic properties in amorphous Ce-alloys. We have focused amorphous Ce-Mn alloys consisting of the rare-earth metal cerium and the transition metal manganese. We have measured the magnetostriction for amorphous Ce-Mn alloys where a large thermal expansion and anomalous temperature dependence observed. The thermal expansion of the low temperature for amorphous Ce-Mn alloys has been found to be controlled by a magnetic field. In the future, we aim at development of the drive actuator element under the control of the temperature and magnetic field. Keywords : Strongly correlated electron, Amorphous alloys, Thermal expansion, Magnetostriction

1 ࡣࡌࡵ࡟ ᕼᅵ㢮ඖ⣲ࢆྵࡴ㔠ᒓ㛫໬ྜ≀ࡸྜ㔠ࡣ㸪ᕼᅵ 㢮ࡢ㟁Ꮚࡀ≉ᐃࡢ㌶㐨㸦_{4f ㌶㐨㸧࡟᮰⦡ࡉࢀࡿࡓ} ࡵᒁᅾᛶࡀᙉࡃ㸪㟁Ꮚྠኈࡢࢡ࣮ࣟࣥ┦஫స⏝ࡀ ↓ど࡛ࡁ࡞࠸ࡓࡵ㸪ᙉ࠸㟁Ꮚ┦㛵㸦ᙉ┦㛵㟁Ꮚ≧ ែ㸧ࢆᐇ⌧ࡍࡿ㸬ࡇࡢᙉ┦㛵㟁Ꮚ≧ែࡣ㸪ᕧ኱⇕ ᐜ㔞࣭ወጁ࡞☢Ẽ┦㌿⛣࣭ᕧ኱☢Ẽ᢬ᢠ࣭␗ᖖ⇕ ⭾ᙇ࣭⇕㟁ኚ᥮≉ᛶ࣭㠀ᚑ᮶ᆺ㉸ఏᑟ࡞࡝ከᙬ࡛ 㨩ຊⓗ࡞≀ᛶࢆ♧ࡍࡇ࡜ࡀ▱ࡽࢀ࡚࠸ࡿࠋࡇࢀࡽ ࡢ≉ᛶࡣ㸪⤖ᬗᵓ㐀ࡸእሙ㸦☢ሙ࣭ ᗘ࣭ᅽຊ࣭ 㟁ሙ➼㸧࡟ࡼࡗ࡚኱ࡁࡃ≉ᛶࢆኚ໬ࡉࡏࡿ㸬ᚑࡗ ࡚ᕼᅵ㢮ࢆྵࡴ㔠ᒓ㛫໬ྜ≀ࡸྜ㔠ࡣ㸪ࡕࡻࡗ࡜ ࡋࡓࢳ࣮ࣗࢽࣥࢢ࡟ࡼࡗ࡚᭷ᮃ࡞ḟୡ௦ࡢ㧗ᶵ⬟ ᮦᩱ࡜ࡋ࡚᭷ຊ࡞ྍ⬟ᛶࢆ⛎ࡵ࡚࠸ࡿ㸬 *1 ᐊ⹒ᕤᴗ኱Ꮫ ࡋࡃࡳ᝟ሗ⣔㡿ᇦ *2 ᐊ⹒ᕤᴗ኱Ꮫ ⎔ቃㄪ࿴ᮦᩱᕤᏛ◊✲ࢭࣥࢱ࣮ *3 ᐊ⹒ᕤᴗ኱Ꮫ ᛂ⏝⌮໬Ꮫ⣔ᑓᨷ  ᡃࠎࡣ㸪୺࡟ᕼᅵ㢮ඖ⣲ࡢࢭ࣒ࣜ࢘㸦_Ce㸧ࢆྵ ࡴ㸪༢⤖ᬗ࠿ࡽᵓ㐀୙つ๎㸦࢔ࣔࣝࣇ࢓ࢫ㸧࡞࡝ ࡢᵝࠎ࡞ᵓ㐀ࢆᣢࡘᕼᅵ㢮໬ྜ≀࠾ࡼࡧྜ㔠ࡢ㛤 Ⓨ࡜㟁Ꮚ≀ᛶ࡟ࡘ࠸࡚◊✲ࢆ⾜ࡗ࡚ࡁࡓ㸬ࡇࢀࡲ ࡛ࡢᡂᯝ࠿ࡽ㸪ᙉ┦㛵㟁Ꮚࡀ㛵୚ࡋࡓᵝࠎ࡞㟁Ẽ ఏᑟᛶࡸ⇕≉ᛶࢆぢฟࡋ࡚ࡁࡓࡀ㸪≉࡟㸪࢔ࣔࣝ ࣇ࢓ࢫ_{(a-)Ce ྜ㔠࡟㛵ࡋ࡚㸪୙つ๎࡞ᵓ㐀࡟࠾࠸࡚} ࡶᙉ┦㛵㟁Ꮚ≧ែࡀᐇ⌧ࡍࡿࡇ࡜ࢆึࡵ࡚ぢฟࡋ ࡓ㸬ࡑࡇ࡛㸪≉࡟࢔ࣔࣝࣇ࢓ࢫྜ㔠ࢆ◊✲ᑐ㇟࡜ ࡋ࡚㸪≀㉁㛤Ⓨࢆ⾜࠸᪂ࡓ࡞ᶵ⬟ᛶᮦᩱ࡜ࡋ࡚ࡢ ྍ⬟ᛶࢆ᥈ࡗࡓ㸬࢔ࣔࣝࣇ࢓ࢫྜ㔠ࡢ◊✲ࡢ฼Ⅼ ࡣ㸪ձ⤖ᬗ໬ྜ≀࡜ࡋ࡚Ꮡᅾࡋ࡞࠸ඖ⣲ᵓᡂࡢྜ 㔠స〇ࡀྍ⬟㸪ղ௵ពࡢ⤌ᡂẚ࡛ไᚚࡋࡓヨᩱస 〇ࡀྍ⬟㸪ճ☢Ẽ␗᪉ᛶࡀ࡞࠸࡞࡝ࡢ≉㛗ࢆᣢࡘ ࡓࡵ㸪≀㉁㛤Ⓨࡢ⮬⏤ᗘࡀ㠀ᖖ࡟㧗࠸㸬ࡉࡽ࡟㸪 ࣐ࢡࣟ࡟ᆒ㉁࡞≉ᛶࡀᚓࡽࢀࡿࡇ࡜࠿ࡽ㸪ᮦᩱ≀ ᛶࡢほⅬ࠿ࡽࡶ᭷฼࡛࠶ࡿ࡜ゝ࠼ࡿ㸬ࡑࡇ࡛ᮏࢱ ࢫࢡࣇ࢛࣮ࢫ◊✲࡛ࡣ㸪ᕼᅵ㢮ඖ⣲ࡢ_{Ce ࢆ୰ᚰ࡜} ࡋࡓ࢔ࣔࣝࣇ࢓ࢫ࡞࡝ࡢᵝࠎ࡞ᵓ㐀ࢆᣢࡘ㔠ᒓ㛫