準結晶とバルク金属ガラスの 軟X線発光分光

名古屋大学大学院

工学研究科 量子工学専攻

曽田 一雄

PF090113

To understand the microscopic origin of their structural stabilities

and unique properties

Collaborators

• 犬飼 学、宮崎 秀俊、太田 俊二、鈴木 孝治、

加藤 政彦、八木 伸也、長谷川 正（名大院工）

• 竹内 恒博（名大エコ研）

• 佐藤 洋一（愛教大）

• 水谷 宇一朗（豊田理化学研）

• 和田 武、横山 嘉彦（東北大金研）

• 西山 信行（ RIMCOF ）

• 手塚 泰久（弘前大）

• 岩住 俊明（阪府大）

Agenda

複雑合金系の電子構造と原子配列

• ２次元準結晶 2-D QuasiCrystal

• バルク金属ガラス Bulk Metallic Glass

軟X線発光分光 XES＋光電子分光 PES

＋第一原理クラスター計算 DV-Xα To understand the microscopic origin of

their structural stabilities

and unique properties

まとめ（XESへの期待）

2-D QC Al-Co-Ni

X-ray Laue diffraction pattern taken from the 10-fold axis.

1

2

3

4 5 6

7

8

9 10

Microscopic origin for unique atomic arrangement ?

an ingot of Al72Co16Ni12

[1] M.Krajci et al., Materials Sci. & Eng. 294-296, 548 (2000).

0

1 TOTAL

Al

Ni

-5 0 5 10

Co

BINDING ENERGY / eV

Approximant Al68.60Co14.88Ni16.52 [1]

Pseudogap in Al pDOS ? >>> Hume-Rothery-type

stabilizing mechanism Strong Co-Al interaction ?

>>> Ni central ring

Pd-M-P (M = Ni, Cu) BMG

1

2

3

4

5 6

7

10 106 K/s 10 K/s

Bulk Metallic Glass

Critical cooling rate

Amorphous Metal High resistance to crystallization of thermodynamically metastable BMG

Microscopic origin for large stability ?

• Structure-induced Minimum in Free Electron DOS [1]

Pseudo-Gap Formation ? • Role of TM d States ?

EF

ENERGY

DO

S

XES measurement

EB=EC (2p) - hv

hnex (SR)

e-

hnemi

Sample

Detector

Grating

IPES

EK hnex

XPS EF

hnex

elastic

hnemi

IXES

hnex XES

E hnemi

Co2p

EF

EB

hnemi Ni3d Co3d

0 IXES

0

IXES

Ni2p

hnex

Ni2p EB

IXES

Co2p

0

Cluster Calculation • Discrete Variational Xa (DV-Xa) method [1] • the available code SCAT [2] tuned up

for faster calculation with lager cluster

[1] H. Adachi et al., J. Phys. Soc. Jpn. 45 (1978) 875-883. [2] http://www.dvxa.org/ [3] E. Abe et al., Phys.Rev. Lett 84 (2000) 4609. [4] M. Inukai et al., Z. Kristallogr. in press.

TEM image of Al-Co-Ni [3]

Triple-layer Unit Cluster [4]

B-A-B cluster > A-layer DOS +

A-B-A cluster > B-layer DOS

http://www.dvxa.org/

TM Arrangement

(a) Ni inner ring model (b) Co inner ring model

Al-Co-Ni

(a)

(b)

-50510

TotalAlCoNi

Ni XESCo XESXPS

DE

NS

ITY

OF

ST

AT

ES

/ e

V-1

clu

ste

r-1

INT

EN

SIT

Y / a

rb.u

nits

BINDIGN ENERGY / eV

Al72

Co16

Ni12

Al81

Co15

Ni15

H50

1

0

(a)

(b)

0

0

50

75

25

2525

05

NiCoSUM

Ni XES

Co XES

XPS

DE

NS

ITY

OF

ST

AT

ES

/ e

V-1

clu

ster

-1

INT

EN

SIT

Y /

arb

. unit

s

BINDING EMERGY / eV

Ni inner ring

Co inner ring

0

10

0

1

0

10

20

Ni-Co mixed

0

10

Possible Co-Ni Mixing

Raman Spectrum

0

150

300

-10 -8 -6 -4 -2 0 2 4 6 8

RXESELASTICUPDOS

RXESELASTICUPDOS

RAMAN SHIFT / eV

Co

Cu

Al65Co20Cu15

2p

hnemi

EF

3d

hnex

中間状態

Valence-band Structure

-505101520

P3spP3sp x 50Ni3dPd3d

INT

EN

SIT

Y /

arb

. u

nit

s

DO

S /

arb

. u

nit

s

BINDING ENERGY / eV

P Ka XES

0

0

0

0

1

0

1

XPS

hn / eV85

40

7940

Pd L2,15

XES

Pd40

Ni40

P20

XESvsXPS_Pd40Ni40P20

Pd

Ni

P

P P

Pd3Ni6P cluster

Energy shift of P XES ?

Microscopic Origin of High Structural Stability of BMG

[1] C. Park et. al., Mater. Trans. JIM, 40, (1999) 491. [2] M. Vennstörm, J. Höwing et al., J. Solid. State. Chem., 177 (2004) 1449.

Pd3Ni6P cluster (PdNi2P [2])

Preferential Clusters [1]

• Chemical bond formation

Reducing U

• Network Formation of Local Clusters

Increasing S

DOS of P ? Pseudogap ? 金属性の強いZr-TM-Al系BMGの安定化機構は？

Summary & Needs Summary for QC

• TM 3d DOS > Co-Ni mixed arrangement • Composition dependence ?

decagonal ring in Co-rich phase and broken symmetry in Ni-rich one

• Psuedogap in Al DOS ? > Al K or L XES • Unoccupied DOS in Resonant Raman ?

Summary for BMG

• Rigid local units + their flexible network formation

• Energy of P DOS ?

• Role of pseudogap (in more metallic Zr-BMG) ?

Needs

• K, L XES of light elements (Al, P etc.) • Careful energy-calibration with XPS et al.

• High stability