3C03Ỉ⣲⤖ྜ⣔᭷ᶵᙉㄏ㟁యࡢప㧗ᅽᵓ㐀

(1 ⏘⥲◊࣭ගᢏ⾡, 2 ᮾ኱㝔ᕤ) ‫⇃ۑ‬஭ ⋹ඣ 1, ᇼෆ బᬛ㞝 1, ༑಴ ዲ⣖ 1,2࠙⥴ゝࠚ᭷ᶵࡢ㓟࡜ሷᇶࡀࠊࡑࢀࡒࢀࣉࣟࢺࣥࢻࢼ࣮ཬࡧࣉࣟࢺࣥ࢔ࢡࢭࣉࢱ࣮࡜ࡋ࡚Ỉ⣲⤖ྜ࡟ࡼࡗ࡚⤖ࡤࢀࡓ㉸ศᏊᙉㄏ㟁య࡛ࡣࠊỈ⣲⤖ྜ㒊఩ࡢᚤᑠ࡞ኚ໬ࡀࠊ⤖ᬗ඲యࡢศᴟࡢⓎ⌧ࢆㄏ㉳ࡋ࡚࠸ࡿࡇ࡜ࡀ≉㛗࡛࠶ࡿࠋᡃࠎࡣࠊࡇࢀࡲ࡛࡟࠸ࡃࡘ࠿ࡢỈ⣲⤖ྜ⣔ᙉㄏ㟁య࡟㛵ࡋ࡚ࠊỈ⣲⤖ྜ㒊఩࡟࠾ࡅࡿỈ⣲⤖ྜࡢ㠀ᑐ⛠ᛶࠊ࠶ࡿ࠸ࡣࣉࣟࢺࣥ⛣ື࡞࡝ࡢᵓ㐀ኚ໬ࡀࡶࡓࡽࡍศᴟⓎ⌧࡟㛵ࡍࡿ⪃ᐹࢆ⾜ࡗ࡚ࡁࡓ[1]ࠋ࡞࠿࡛ࡶࠊࣇ࢙ࢼࢪࣥ(Phz)࡜࢔ࢽࣝ㓟(H2xa)࠿ࡽ࡞ࡿᙉㄏ
㟁యࡣከẁ㝵ࡢᵓ㐀㌿⛣࡜」ᩘࡢᙉㄏ㟁┦ࢆࡶࡘࡇ࡜ࡀ▱ࡽࢀ࡚࠸ࡿࠋࡇࢀࡲ࡛࡟ X ⥺࠶ࡿ࠸ࡣ୰ᛶᏊᅇᢡ࡞࡝ࡢᐇ㦂࡟ࡼࡾࠊ୍ḟඖỈ⣲⤖ྜ㙐ෆ࡟࠾ࡅࡿࣉࣟࢺࣥࡢࢃࡎ࠿࡞ኚ఩ࡀ୰㛫ᗘ㡿ᇦ(FE-I ┦)࡟࠾ࡅࡿศᴟࡢ㉳※࡜࡞ࡿ[2]ࡇ࡜࡟ຍ࠼ࠊࡉࡽ࡟ప ࡛ࡣ୙ᩚྜ┦ࢆ⤒࡚ᇶᗏ≧ែ(FE-II ┦(H2ca)ࠊFE-III ┦(H2ba))࡬࡜㏲ḟ┦㌿⛣ࢆ♧ࡍࡇ࡜ࡀ᫂ࡽ࠿࡟࡞ࡗ࡚࠸ࡿ[3]ࠋ௒ᅇࠊࡇࢀࡽ࡟ຍ࠼ࠊࣇࢵ⣲⨨᥮య(H2fa)ࢆྵࡵࡓ Phz-H2xa ༢⤖ᬗࡢ㧗ᅽ࡟࠾ࡅࡿㄏ㟁ᣲື࡜ᵓ㐀ኚ໬࡟㛵ࡋ࡚᪂ࡓ࡞▱ぢࢆᚓࡓࡢ࡛ሗ࿌ࢆ⾜࠺ࠋ࠙ᐇ㦂ࠚㄏ㟁య༢⤖ᬗࡣᐃἲ࡟ᚑ࠸ㄪᩚࡋࡓࠋᨺᑕග X ⥺ᅇᢡᐇ㦂ࡣ㧗࢚ࢿࣝࢠ࣮ຍ㏿ჾ◊✲ᶵᵓ(KEK)࣭≀㉁ᵓ㐀⛉Ꮫ◊✲ᡤ࣭ᨺᑕග᪋タ(PF)࡟࠾ࡅࡿࣅ࣮࣒ࣛ࢖ࣥ BL-1Aࠊ8A, 8B ࡛⾜࠸ࠊ೫ග㟁☢▼࠿ࡽࡢⓑⰍගࢆ஧⤖ᬗศගჾ(Si(111))࡟ࡼࡗ࡚༢Ⰽ໬ࡋࡓ X ⥺ (! = 0.6877Å ࢆ⏝࠸ࠊ࢖࣓࣮ࢪࣥࢢࣉ࣮ࣞࢺ࡟ࡼࡗ࡚᣺ື෗┿ࡢ᧜ᙳࢆ⾜ࡗࡓࠋ㧗ᅽᅇᢡᐇ㦂ࡣࠊBe ࣆࢫࢺࣥࢩࣜࣥࢲ࣮ࢆ⏝࠸ࡓࢡࣛࣥࣉᆺࢭࣝ࡟ࡼࡗ࡚༢⤖ᬗヨᩱࢆຍᅽࡋࠊHe ᚠ⎔ᆺ෭෾ᶵࢆ⏝࠸࡚෭༷ࢆ⾜ࡗࡓࠋప ࡟࠾ࡅࡿᅽຊࡢ㍑ṇ࡟ࡣ NaCl ࡢ᱁Ꮚᐃᩘࢆ⏝࠸ࡓࠋ࠙⤖ᯝ࡜⪃ᐹࠚ᪤࡟ሗ࿌ࡋࡓ㏻ࡾࠊPhz-H2ca ཬࡧ Phz-H2ba ࡣࠊᖖᅽ࡛ࡑࢀࡒࢀ TcI = 253 K, 138K ࡛ᵓ㐀┦㌿⛣ࢆ♧ࡋᙉㄏ㟁య࡜࡞ࡿ[2]ࡀࠊࡉࡽ࡟ప ࡛ࡣ TcICᗘ௨ୗ࡛ฟ⌧ࡍࡿ୙ᩚྜ┦ࢆ⤒࡚ࠊࡑࢀࡒࢀ TcII = 137 K, 98 K ௨ୗ࡛ࡣ୰㛫┦(TcII < T < TcI, FE-I ┦)࡜ࡣูࡢᙉㄏ㟁┦ࡀฟ⌧ࡍࡿࠋᇶᗏ≧ែ࡛࠶ࡿࡇࡢ┦ࡢᵓ㐀ࡣሷ⣲⨨᥮య࡜⮯⣲⨨᥮య࡛␗࡞ࡾࠊࡑࢀࡒࢀ 2 ಸ࿘ᮇ(q =(1/2 1/2 1/2))ཬࡧ 3 ಸ࿘ᮇ(q1 = (1/3 ±1/3 0), q2 = (2/3 ±2/3 0))ࡢ㛗࿘ᮇᵓ㐀ࢆࡶࡘࡇ࡜ࡀᅇᢡᐇ㦂࡟ࡼࡾ☜ㄆࡉࢀࡓ[3]ࠋࡇࢀࡽࡢ⤖ᬗࡢ㟼Ỉᅽୗ࡟࠾ࡅࡿㄏ㟁ᣲືࡢ ᐃ࠿ࡽࠊሷ⣲⨨᥮య࡛ࡣᅽ
ຊࡢቑຍ࡟క࠸ TcI, TcII ࡜ࡶ࡟⦆ࡸ࠿࡟ୖ᪼ࡋࠊᴟ኱ࢆ㏄࠼ࡓᚋ࡟⦆ࡸ࠿࡟ୗ㝆࡟㌿ࡌࡿࡇ࡜ࡀ
ࢃ࠿ࡗࡓ(ᅗ 1a)ࠋᖖᅽ࡛ 3 ಸ࿘ᮇࢆ᭷ࡍࡿ⮯⣲⨨᥮య࡛ࡣࠊᅽຊࡢቑຍ࡟కࡗ࡚ࠊTcI ࡀ኱ࡁࡃୖ᪼ࡍࡿ୍᪉ࠊTcII ࡣୗ㝆ࡋࠊ0.3 GPa ௜㏆࡛ᴟᑠࢆ♧ࡋࠊࡇࢀ௨ୖࡢᅽຊ࡛ࡣሷ⣲⨨᥮య࡜ྠᵝࡢᅽຊ౫Ꮡᛶࢆ♧ࡍࠋࡇࢀࡽࡢ⤖ᯝࢆ㋃ࡲ࠼ࠊ0.3 GPa ௜㏆࡛ࡢ␗ᖖࡢཎᅉࢆㄪ࡭ࡿࡓࡵ࡟ࠊ㧗ᅽప ୗ࡛ᅇᢡᐇ㦂ࢆ⾜ࡗࡓ࡜ࡇࢁࠊప ࡟࠾ࡅࡿ㛗࿘ᮇᵓ㐀ࡀ 3 ಸ࠿ࡽሷ⣲⨨᥮య࡜ྠᵝࡢ 2 ಸ
࿘ᮇ(q = (1/2 1/2 1/2))࡬࡜ኚ໬ࡋ࡚࠸ࡿࡇ࡜ࡀࢃ࠿ࡗࡓࠋᫎ㐍㠃ࡢᾘኻ࡟ᑐᛂࡍࡿ h0l (h+l = odd)཯ᑕཬࡧಸ࿘ᮇ࡟ᑐᛂࡍࡿ h+1/2 k+1/2 l+1/2 ཯ᑕᙉᗘࡢ ᗘኚ໬(ᅗ 2a)࠿ࡽࠊࡑࢀࡒࢀࡢㄏ㟁㌿⛣ࡣ P21/n ࠿ࡽ P21 ࡬ࡢᵓ㐀㌿⛣ࠊཬࡧಸ࿘ᮇᵓ㐀ࡢᙧᡂ࡜ᑐᛂࡋ࡚࠾ࡾࠊࡇࡢ⤖ᬗࡢ㧗ᅽୗ(P >0.3 GPa)ࡢᵓ㐀ኚ໬ࡣࠊሷ⣲⨨᥮యࡢᖖᅽࡢሙྜ࡜ྠࡌ࡛࠶ࡿࡇ࡜ࡀ᫂ࡽ࠿࡟࡞ࡗࡓࠋ୍᪉ࠊᖖᅽ࡛ࡣప ࡲ࡛ᖖㄏ㟁ࢆ♧ࡍࣇࢵ⣲⨨᥮యࡢሙྜࠊ᫖ᖺࡢᮏウㄽ఍࡛ሗ࿌[4]ࡋࡓ㏻ࡾࠊ
ᅽຊࢆ༳ຍࡍࡿࡇ࡜࡛ᙉㄏ㟁┦ࡀฟ⌧ࡋࠊP > 0.7 GPa ࡛ࡣ ᗘኚ໬࡟ࡼࡾࠊ⮯⣲⨨᥮యࡢሙྜ࡜ࡼࡃఝࡓ㏲ḟ┦㌿⛣ࡀほ ࡉࢀࡓࠋ㧗ᅽୗࡢᅇᢡᐇ㦂ࢆ⾜ࡗࡓ࡜ࡇࢁࠊ᭱ప ┦࡛ࡣࠊ 0.7 < P< 0.8 GPa ࡢሙྜ 3 ಸࠊP > 0.8 GPa ࡢሙྜ 2 ಸࡢ㛗࿘ᮇᵓ㐀ࢆ᭷ࡍࡿࡇ࡜ࡀࢃ࠿ࡗࡓࠋࡑࢀࡒࢀࡢ┦࡟࠾ࡅࡿ㉸᱁Ꮚ཯ᑕࡢ㏫᱁Ꮚ࣋ࢡࢺࣝࡣࠊq = (1/3 1/3 1/3), (2/3 2/3 2/3) ཬࡧ q = (1/2 1/2 0)

100

00

FE!I
FE!IC

TcII

FE!II
2!fold0.5

TcIC

PhzH2ca
1

1.5

200

2

Temperature (K)

0

TcI
FE!I
TcIC

FE!III
3!fold
00.5

0.5

1.5

20.015

PhzH2ba0.01

h0l0.005

ONX

N

HOOH

½"½"½"

00X

50

FE!II
2!fold

1.5

Phz

200

250

3000.006

P ="0.89"GPa (@RT)

2࡛࠶ࡾࠊ⮯⣲⨨᥮యࡢሙྜ࡜ࡣỈ⣲⤖ྜ㙐㛫(//c ㍈)ࡢ࿘ᮇࡀ
␗࡞ࡿࡶࡢࡢࠊࡼࡃఝࡓᵓ㐀࡛࠶ࡿࡇ࡜ࡀ♧၀ࡉࢀࡓࠋࡲࡓࠊ୰㛫┦࡛࠶ࡿ FE-I ┦ࡣࠊh0l (h+l = odd)ࡢᣦᩘࢆ᭷ࡍࡿ

Intensity (arb. unit)ᅗ 1 Phz-H2xa ࡟࠾ࡅࡿ ᗘ-ᅽຊ┦ᅗ

PhzH2fa

0.004

h0l0.002

1/3"1/3"1/3

཯ᑕࡀほ ࡉࢀࡿ (ᅗ 2b,c)ࡇ࡜࠿ࡽࠊሷ⣲/⮯⣲⨨᥮య࡜ྠ0.000ᆺࡢᵓ㐀ࢆࡶࡘࡇ࡜ࡀ᫂ࡽ࠿࡟࡞ࡗࡓࠋ

050࡛ฟ⌧ࡍࡿ㛗࿘ᮇᵓ㐀ࢆࡶࡘᙉࢆ⪃៖ࡍࡿ࡜ࠊ࢖࢜ࣥᛶࡢỈ⣲⤖ྜ㙐(HPhz+ … Hca- …
HPhz+ … Hca-)࡜ࠊ୰ᛶࡢỈ⣲⤖ྜ㙐(Phz … H2ca … Phz୰ᛶ✀࡜࢖࢜ࣥᛶ✀ࡀ 2:1 ࡛ඹᏑࡋࡓ⤖ᯝ࡜㢮᥎࡛ࡁࡿࠋࡍ

250

300

P ="1.09"GPa (@RT)

PhzH2fa

0.010

h0l0.005… H2ca)࡜ࡀඹᏑࡍࡿᵓ㐀࡛࠶ࡿࡇ࡜ࡀᙉࡃ♧၀ࡉࢀࡿࠋࡲ
ࡓࠊ⮯⣲⨨᥮యࡸࣇࢵ⣲⨨᥮య࡛ぢࡽࢀࡿ 3 ಸ࿘ᮇࡢᵓ㐀ࡣ

200

0.015

Intensity (arb. unit)ࡿᵓ㐀࡛ࡣ 2 ✀㢮ࡢỈ⣲⤖ྜ㙐ࡀ஺஫࡟✚ᒙࡋ࡚࠸ࡿࡇ࡜150c)

ࣥ⛣ື࡟ࡼࡗ࡚⏕ࡌࡓ࢖࢜ࣥᛶ✀ࡢᏑᅾࡀ☜ㄆࡉࢀ࡚࠸ࡿࠋ
ࡢ✵㛫⩌(monoclinic C1)࠿ࡽᚓࡽࢀ

100

Temperature (K)ㄏ㟁┦࡛ࡣࠊගᏛࢫ࣌ࢡࢺࣝࡢ ᗘ౫Ꮡᛶ [5]࠿ࡽࠊࣉࣟࢺሷ⣲⨨᥮యࡢᖖᅽప150b)

H2xa"(X"="F,"Cl,Br)

Pressure (GPa)ࡇࢀࡽࡢ⣔࡟࠾࠸࡚ࠊప

100

Temperature (K)O

TcII
1PhzH2ba

1FE!III
3!foldPhzH2fa200
PE

TcIC
TcII

Pressure (GPa)

300

100

00.02

P ="0.48"GPa (@RT)

FE!IC

FE!II
2!foldPressure (GPa)

c)

FE!I

1000a)TcI

PE

Intensity (arb. unit)

200b) 300

TcI

Temperature(K)Temperature (K)a) 300 PE½"½"0"
0.000

050

100

150200250300Temperature (K)࡞ࢃࡕࠊࡇࡢ⣔࡟࠾ࡅࡿప ᙉㄏ㟁┦ࡢศᴟ㉳※ࡣࠊ ᗘࡢᅗ 2 ᅽຊୗ࡟࠾ࡅࡿ㉸᱁Ꮚ཯ᑕῶᑡཬࡧຍᅽ࡟ࡼࡗ࡚཰⦰ࡋࡓ᱁Ꮚ࡟ㄏ㉳ࡉࢀࡓࣉࣟࢺࣥᙉᗘࡢ ᗘኚ໬⛣ືࡀࠊศᏊෆཬࡧỈ⣲⤖ྜ㙐࡟⏕ࡌࡉࡏࡓ㠀ᑐ⛠ᛶ࡛࠶ࡾࠊȧࢫࢱࢵࢡ(//b ㍈)᪉ྥࡢࢡ࣮ࣟࣥ
཯Ⓨࢆపῶࡉࡏࡿࡓࡵ࡟୰ᛶ✀࡜࢖࢜ࣥᛶ✀ࡀ஺஫࡟✚ᒙࡍࡿᵓ㐀ࢆᙧᡂࡋࡓࡶࡢ࡜⪃࠼ࡽࢀࡿࠋ
References[1] S. Horiuchi et al., Nat. Mater., 7, 357(2008)[2] R. Kumai et al., J. Am. Chem. Soc., 129, 12920 (2007)[3] S. Horiuchi et al., J. Mater. Chem., 19, 4421 (2009).
[4] ᇼෆࡽ, ศᏊ⛉Ꮫウㄽ఍ 2008[5] J. Fujioka et al., submitted.