࡮ታᣉ⺖㗴⇟ภ㧦2005B0785࡮ታᣉ⺖㗴ฬ㧦Micro-XMCD ߦࠃࠆ⏛᳇࠼࠶࠻ߩ⏛ൻ෻ォߦ㑐ߔࠆ⎇ⓥ
࡮ታ㛎⽿છ⠪ ㄭ⮮␭ᴦ㧔⑺↰⋵↥ᬺᛛⴚ✚ว⎇ⓥ࠮ࡦ࠲࡯㧕࡮౒หታ㛎⠪ ㋈ᧁၮኡ㧔㜞ノᐲశ⑼ቇ⎇ⓥ࠮ࡦ࠲࡯㧕㧘᦭᣿㗅㧘ජ⪲㓉㧔⑺↰⋵↥ᬺᛛⴚ✚ว⎇ⓥ࠮
ࡦ࠲࡯㧕㧘㜞၂᣽ผ㧘ᴡ᧛⋥Ꮖ㧔㜞ノᐲశ⑼ቇ⎇ⓥ࠮ࡦ࠲࡯㧕࡮૶↪ࡆ࡯ࡓ࡜ࠗࡦ㧦BL39XU࡮ታ㛎⚿ᨐ㧦
1. ߪߓ߼ߦ2005 ᐕߦߪု⋥⏛᳇⸥㍳ᣇᑼߩࡂ࡯࠼࠺ࠖࠬࠢ࠼࡜ࠗࡉ㧔HDD㧕߇Ꮢ⽼ൻߐࠇߚߩࠍᆎ߼㧘ߘߩᓟ߽ฦࡔ࡯ࠞ࡯߆ࠄหᣇᑼߩ HDD ߇⊒ᄁߐࠇࠃ߁ߣߒߡ߅ࠅ㧘޿ࠃ޿ࠃ HDD ᬺ⇇ߢߪ㕙ౝ⏛᳇⸥㍳ᣇᑼ߆ࠄု⋥⏛᳇⸥㍳ᣇᑼ߳ߩ⒖ⴕ߇⃻ታߦߥߞߡ߈ߚ㧚ߒ߆ߒ㧘ု⋥⏛᳇⸥㍳ߣ޿߃ߤ߽㧘ࠣ࡜࠾ࡘ࡜࡯ဳㅪ⛯ᇦ૕ߢߪ⸥㍳ࡆ࠶࠻ߩᾲ⏛᳇✭๺ߦࠃࠆ⸥㍳ኒᐲߩ਄㒢ߪ 600 Gbit/in2 ߣ⸒ࠊࠇߡ޿ࠆ
[1]㧚1 Tbit/in2 એ਄ߩ㕙⸥㍳ኒᐲࠍ㆐ᚑߔࠆᣇᑼߣߒߡ㧘޿ߊߟ߆ߩᣂߚߥ߽ߩ߇ឭ᩺ߐࠇߡ޿ࠆ߇㧘ߘߩਛߢ߽න⏛඙᭴ㅧࠍᜬߟ⏛᳇࠼࠶࠻ࠍ๟ᦼ⊛ߦ 2 ᰴర㈩೉ߒߚࡄ࠲࡯ࡦ࠼ࡔ࠺ࠖࠕ߇ᦨ߽᦭ജⷞ
ߐࠇߡ޿ࠆ㧚ᚒ‫ߪޘ‬㓸᧤ࠗࠝࡦࡆ࡯ࡓ㧔FIB㧕ࠍ↪޿ߡ⏛᳇࠼࠶࠻ࠕ࡟ࠗߩ૞⵾ࠍⴕ޿㧘࠼࠶࠻㑆㓒ߣ㕒⏛⋧੕૞↪ߩ㑐ଥ߆ࠄࡄ࠲࡯ࡦ࠼ࡔ࠺ࠖࠕߩ⸳⸘ᜰ㊎ߦߟ޿ߡ⎇ⓥࠍⴕߞߡ߈ߚ[2]㧚ߒ߆ߒ㧘FIBടᎿߪᄢ㕙ⓍߩടᎿߦߪะ޿ߡ޿ߥ޿ߚ߼㧘᳢↪ߩ⏛᳇᷹ቯⵝ⟎㧔VSM ߿ SQUID㧕ߢߪᗵᐲ߇⿷ࠅߕ㧘⏛᳇᷹ቯ߇࿎㔍ߢ޽ߞߚ㧚ߘߎߢ㧘ࡑࠗࠢࡠࡆ࡯ࡓ X ✢ߦࠃࠆ X ✢⏛᳇౞ੑ⦡ᕈ㧔micro-XMCD㧕ࠍ↪޿ߡ㧘FIB ߢ૞⵾ߒߚ⏛᳇࠼࠶࠻ࠕ࡟ࠗߩၮ␆⊛ߥ⏛᳇․ᕈࠍ⹏ଔߒߚ㧚

2. CoPt ⏛᳇࠼࠶࠻ࠕ࡟ࠗ ⏛᳇࠼࠶࠻ࠕ࡟ࠗ⹜ᢱߪ㧘੍߼ࠟ࡜ࠬ࠺ࠖࠬࠢၮ᧼ߦᚑ⤑ߒߚ⏛ᕈ⤑ࠍ FIB ߦࠃࠅࡄ࠲࡯࠾ࡦࠣߔࠆߎߣߢ૞⵾ߒߚ㧚⏛ᕈ⤑ߩ⤑᭴ᚑߪ Co80Pt20(at.%)(15 nm)/Au(6 nm)/Ti(5 nm)/glass ߢࡑࠣࡀ࠻ࡠࡦࠬࡄ࠶࠲ᴺߦࠃࠅቶ᷷ߢᚑ⤑ߒߚ㧚ࡄ࠲࡯࠾ࡦࠣߪ FIB ⵝ⟎㧔SII ࠽ࡁ࠹ࠢࡁࡠࠫ࡯␠⵾㧘
SMI2050MS㧕ߢⴕߞߚ㧚ടᎿߦߪടㅦ㔚࿶ 30 keV㧘⹜ᢱ㔚ᵹ 1 pA ߩ Ga ࠗࠝࡦࠍ↪޿ߚ㧚ో૕ߩ⹜ᢱࠨࠗ࠭ߪ࠺ࠖࠬࠢၮ᧼߆ࠄಾࠅ಴ߒߚ 5 mm ⷺၮ᧼ߢ޽ࠆ߇㧘࠼࠶࠻ࠕ࡟ࠗߪߘߩਛᄩㇱಽߩ 8 Pm2㗔ၞߩߺߦ㈩⟎ߒߚ㧚࠼࠶࠻ߩᄢ߈ߐߪ㧝ㄝ 70㧘100㧘150 nm ߩᱜᣇ࠼࠶࠻ߢ࠼࠶࠻㑆㓒ߪ 100 nmߢ࿕ቯߣߒߚ㧚

3. XMCD ታ㛎⏛᳇࠼࠶࠻ࠕ࡟ࠗ߅ࠃ߮ടᎿߔࠆ೨ߩ CoPt ㅪ⛯⤑ߩ⏛᳇․ᕈߩ⹏ଔߪ Pt L3 ๆ෼┵㧔hQ=11.6 keV㧕ߢⰯశᴺࠍ↪޿ߚ XMCD ᷹ቯߦࠃࠅⴕߞߚ㧚ࡆ࡯ࡓ࡜ࠗࡦߪ BL39XU ࠍ૶↪ߒߚ㧚8 Pm2 㗔ၞౝߩ⏛ ᳇ ࠼ ࠶ ࠻ ߩ ߺ ߩ XMCD ᷹ ቯ ࠍ ߔ ࠆ ߚ ߼ ߦ 㧘 ੑ ⚿ ᥏ ಽ శ ེ ߢ න ⦡ ൻ ߐ ࠇ ߚ X ✢ ࠍ
Kirkpatrick-Baez(K-B)ࡒ࡜࡯ߢ 2.4(H)u2.5(V) Pm2 ߦ㓸శߒߚ[3]㧚߹ߚ㧘I20 Pm ߩࡇࡦࡎ࡯࡞ࠍ K-Bࡒ࡜࡯ߣ⹜ᢱߩ㑆ߦ㈩⟎ߔࠆߎߣߢ㧘ᢔੂశ߿ㅅశࠍᛥ೙ߒߚ㧚XMCD ࡅࠬ࠹࡝᷹ࠪࠬቯߪ㧘2005ᐕᄐߦᣂߚߦዉ౉ߒߚࡑࠗࠢࡠࡆ࡯ࡓ X ✢↪ߩዊဳ㔚⏛⍹㧔ࡐ࡯࡞ࡇ࡯ࠬࠡࡖ࠶ࡊ 10 mm㧕ߣ⹜ᢱ࿁ォࠬ࠹࡯ࠫࠍ↪޿㧘ᦨᄢ 8 kOe ߩ⏛႐ਛߢⴕߞߚ[4]㧚

− 31 −

4. ⚿ᨐ߅ࠃ߮⠨ኤ(a) Unpatterned film

0.15
0.10

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XMCD (arb. units)

XMCD (arb. units)(b) Dot size 150 nm

0.15

0.05
0.00
-0.05

0.05
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-0.05

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-4-3-2-1

01234-4-3-2

Applied field (kOe)(c) Dot size 100 nm

0.1501234234(d) Dot size 70 nm

0.15
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XMCD (arb. units)

0.10
XMCD (arb. units)-1

Applied field (kOe)

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-4-3-2-1

01

23-4

4-3-2-1

01

Applied field (kOe)

Applied field (kOe)

Fig.1 ടᎿ೨ߩ CoPt ㅪ⛯⤑(a)ߣ CoPt ⏛᳇࠼࠶࠻ࠕ࡟ࠗ(b㨪d)ߩ Pt L3 ๆ෼┵ߢߩ XMCD ࡅࠬ࠹࡝ࠪࠬᦛ✢㧚࠼࠶࠻ࠨࠗ࠭ߪ(b) 150 nm㧘(c) 100 nm㧘(d) 70 nm㧚

 Fig.1 ߦടᎿ೨ߩ CoPt ㅪ⛯⤑(a)ߣ⏛᳇࠼࠶࠻ࠕ࡟ࠗ(b㨪d)ߩ XMCD ࡅࠬ࠹࡝ࠪࠬᦛ✢ࠍ␜ߔ㧚ߎߎߢ㧘ශട⏛႐ᣇะߪ⤑㕙ߦኻߒߡု⋥ᣇะ(T=0q)ߢ޽ࠆ㧚߹ߚ㧘Fig.1 ߩ❑ゲߪ Co ߩⰯశᒝᐲߢⷙᩰൻߒߡ޿ࠆߚ߼ߦ㧘⏛ᕈ૕ߩන૏૕Ⓧ޽ߚࠅߩ⏛᳇ࡕ࡯ࡔࡦ࠻ߦᲧ଀ߒߚ୯ࠍ␜ߒߡ޿ࠆ㧚ㅪ⛯⤑ߣ⏛᳇࠼࠶࠻ࠕ࡟ࠗߩ㘻๺ߒߚ⁁ᘒ㧔3 kOe એ਄㧕ߢߩ XMCD ᒝᐲࠍᲧセߔࠆߣ㧘⏛᳇࠼࠶࠻ࠕ࡟ࠗߢߪㅪ⛯⤑ࠃࠅᷫዋߒߡ޿ࠆ㧚߹ߚ㧘࠼࠶࠻ࠨࠗ࠭߇ዊߐߊߥࠆߦߟࠇߡ XMCD ᒝᐲ߇ᷫዋߒߡ޿ࠆߎߣ߇ࠊ߆ࠆ㧚એ೨㧘IBM ߆ࠄ FIB ടᎿߦࠃߞߡ Ga ࠗࠝࡦ߇ㅴⴕᣇะߦ 25 nm ⒟ᐲଚ౉ߒ㧘⏛ൻ߿৻ゲ⏛᳇⇣ᣇᕈࠍᷫዋߐߖࠆߎߣ߇ႎ๔ߐࠇߚ߇[5]㧘੹࿁ߩ⚿ᨐߪࠗࠝࡦߩㅴⴕᣇะߛߌߢߥߊ㧘ߘࠇߣု⋥ᣇะߦ߽ᛂߜㄟ߹ࠇࠆߎߣߦࠃߞߡ㧘࠼࠶࠻ߩᄖ๟ㇱߢ⏛ൻߩᷫዋࠍᒁ߈⿠ߎߒߚߣ⠨߃ࠄࠇࠆ㧚࠼࠶࠻ߩᄖ๟ㇱߦ Ga ࠗࠝࡦߩᛂߜㄟߺߦࠃߞߡ⏛ൻࠍᄬߞߚ㗔ၞ㧔᏷ Wd㧕߇↢ᚑߐࠇߚߣ઒
ቯߔࠆߣ㧘Fig.1 ߦ␜ߒߚ XMCD ᒝᐲߩᄌൻ߆ࠄ Wd ߪ 13 nm ⒟ᐲߣ⷗Ⓧ߽ࠆߎߣ߇ߢ߈ࠆ㧚ᰴߦ⹜ᢱ㕙ု⋥ᣇะߩ᛫⏛ജ(Hc)߅ࠃ߮ᱷ⇐⏛ൻ(Mr/Ms)ߪ㧘ㅪ⛯⤑ߢߪ 100 Oe㧘0.1 ߣૐߊ㧘㕙ౝᣇะߦᒝ޿੤឵⚿วߒߚ⏛ო⒖േဳߩ⏛ൻ෻ォᯏ᭴ࠍᜬߟߎߣ߇ផኤߐࠇࠆ㧚৻ᣇ㧘CoPt ⏛᳇࠼࠶࠻ࠕ࡟ࠗߢ
ߪ Hc ߅ࠃ߮ Mr/Ms ߪ 1.5 kOe㧘0.7 એ਄ߦჇടߒߡⷺဳᕈߩ⦟޿ࡅࠬ࠹࡝ࠪࠬᦛ✢ߦᄌൻߒߚ㧚ߎࠇߪ㧘࠼࠶࠻ൻߔࠆߎߣߦࠃࠅ㧘⏛ო⒖േဳ߆ࠄ⏛ൻ෻ォᯏ᭴߇ᄌൻߒߚߚ߼ߣ⸒߃ࠆ㧚ߒ߆ߒ㧘੹࿁ߩ࠼࠶࠻ࠨࠗ࠭ߪࠦࡅ࡯࡟ࡦ࠻㐳ࠃࠅ߽චಽᄢ߈ߊ㧘৻ᢧ⏛ൻ࿁ォࡕ࡯࠼ࠍ᦭ߒߡ޿ࠆߣߪ⠨߃ߦߊ− 32 −޿㧚੹ᓟ㧘Hc ߩⷺᐲଐሽᕈ߆ࠄߤߩࠃ߁ߥ⏛ൻ෻ォᯏ᭴ࠍ᦭ߒߡ޿ࠆ߆ߩᬌ⸛߇ᔅⷐߢ޽ࠆ㧚߹ߚ㧘੹࿁ߩ⚿ᨐ߆ࠄ㧘micro-XMCD ࠍ↪޿ࠆߣ㧘ᓸዊ㗔ၞߩ࠽ࡁ᭴ㅧ⏛ᕈ૕ߩ⏛᳇᷹ቯߦ⠴߃ࠆߛߌචಽߥᗵᐲࠍ᦭ߔࠆߎߣ߇ࠊ߆ߞߚ㧚ࠃߞߡ㧘1 Tbit/in2 ࠍ㆐ᚑߔࠆࡄ࠲࡯ࡦ࠼ࡔ࠺ࠖࠕߦ߅޿ߡ߽ᒝജߥ⹏ଔ࠷࡯࡞ߦߥࠆߣᕁࠊࠇࠆ㧚
5. ߹ߣ߼
 micro-XMCD ࠍ↪޿ߡ㧘8 μm2 㗔ၞߦ૞⵾ߒߚ࠼࠶࠻ࠨࠗ࠭ 70㨪150 nm ߩ CoPt ⏛᳇࠼࠶࠻ࠕ࡟
ࠗߩ⏛᳇᷹ቯࠍⴕߞߚ㧚⏛᳇࠼࠶࠻ࠕ࡟ࠗߩု⋥᛫⏛ജ(Hc)ߪടᎿ೨ߩ CoPt ㅪ⛯⤑ߩ Hc ߣᲧߴ㧘10୚એ਄߽Ⴧടߒ㧘ㅪ⛯⤑ߩ⏛ო⒖േဳߩ⏛ൻ෻ォᯏ᭴߆ࠄᄌൻߒߚߎߣ߇ផኤߐࠇߚ㧚࠼࠶࠻ࠨࠗ࠭
߇ዊߐߊߥࠆ߶ߤ XMCD ᒝᐲ߇ᷫዋߒߡ߅ࠅ㧘FIB ടᎿߦࠃࠅ㧘࠼࠶࠻ᄖ๟ㇱ߇⏛᳇⊛ߦ࠳ࡔ࡯ࠫࠍ
ฃߌ㧘⏛ൻࠍᄬߞߡ޿ࠆߎߣ߇⠨߃ࠄࠇࠆ㧚߹ߚ㧘micro-XMCD ߪᓸዊ㗔ၞߩ࠽ࡁ᭴ㅧ⏛ᕈ૕ߩᒝജߥ⏛᳇⹏ଔᴺߢ޽ࠆߣ⸒߃ࠆ㧚⻢ㄉᣣ㗃ߏᜰዉࠍ⾦ࠅ߹ߔጤፒବ৻᧲ർᎿᬺᄢቇ㐳ߥࠄ߮ߦᄢౝ৻ᒄ⑺↰⋵㜞ᐲᛛⴚ⎇ⓥᚲฬ⹷ᚲ㐳ߦᷓ⻢޿ߚߒ߹ߔ㧚ᧄ⎇ⓥࠍㆀⴕߔࠆߦᒰߚࠅ㧘ᧄᄙ⋥᮸೽ᚲ㐳ߥࠄ߮ߦ㜞ᯅᘕ๋਄Ꮸ⎇ⓥຬߦߪߏഥ⸒
ࠍ޿ߚߛ߈߹ߒߚ㧚ᷓߊᗵ⻢↳ߒ਄ߍ߹ߔ㧚ᧄ⎇ⓥߩ৻ㇱߪ⑼ቇᛛⴚᝄ⥝ᯏ᭴㧘⑺↰⋵࿾ၞ⚿㓸ဳ౒ห⎇ⓥ੐ᬺ‫ޟ‬ᰴ਎ઍ⏛᳇⸥㍳ᛛⴚߣ⣖ක≮ᔕ↪ᛛⴚ㐿⊒‫৻ߩޠ‬Ⅳߣߒߡⴕࠊࠇߚ㧚ෳ⠨ᢥ₂[1] ᧄᄙ⋥᮸, ାቇᛛᴺ, MR2004-31 (2004).
[2] ㄭ⮮␭ᴦ, ⚻ᓼᢅ᣿, 㜞ᯅᘕ๋, ᧄᄙ⋥᮸, ᄢౝ৻ᒄ, ᣣᧄᔕ↪⏛᳇ቇળ⹹, ឝタ੍ቯ (2006).
[3] M. Takagaki, M. Suzuki, N. Kawamura, H. Mimura and T. Ishikawa, The 8th International
Conference on X-ray Microscopy, 26-30, July 2005, Himeji, Japan.
[4] M. Takagaki, M. Suzuki, N. Kawamura, Y. Kondo, J. Ariake, T. Chiba, H. Mimura, T. Ishikawa,
The 9th International Conference on Synchrotron Radiation Instrument, 28 May-2 June, 2006,Daegu, Korea.
[5] T. Rettner, S. Anders, T. Thomson, M. Albrecht, Y. Ikeda, M. E. Best, B. D. Terris, IEEE Trans.
Magn., 38, 1725 (2002).

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