YBCO次世代超電導線材のMO磁束観察法による特性評価

YBCO線材のMO法による評価
低温工学協会九州・西日本支部研究会 2006 July 20-22
MO装置
開発
Core part of RTR-MOI
Photograph of core part
Superconductivity Research Laboratory (SRL) - ISTEC
YBCO線材のMO法による評価
低温工学協会九州・西日本支部研究会 2006 July 20-22
MO装置
開発
MOIに用いる磁気光学膜の作製
The indicator films are necessary to observe MO images.
#1
#2
#3
#4
R1
20
20
20
20
R2
6.5
6.4
6.7
6.9
R3
10
10
10
10
R4
0.13
0.14
0.12
0.11
R5
-
R6
2.5
2.5
2.5
2.5
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ÅB
A lot of defects !
We obtain high quality
MO indicator films !
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ÅB
Low defect density !
Superconductivity Research Laboratory (SRL) - ISTEC
YBCO線材のMO法による評価
低温工学協会九州・西日本支部研究会 2006 July 20-22
素線評価
初期のIBAD/PLD線材の磁束侵入の様子
IBAD/PLD
10mT
20mT
30mT
40mT
40K ZFC
Fujikura #106880
50mT
60mT
Defects
10mm
70mT
80mT
90mT
100mT
Remanent
IBAD/PLD線材への磁束侵入は左右均一
Dendriticな磁束侵入がµmオーダで折れ曲がっている
バッファ層の粒界の細かさを反映している
Superconductivity Research Laboratory (SRL) - ISTEC
YBCO線材のMO法による評価
Previous study of MOI on coated conductors
in
USA
低温工学協会九州・西日本支部研究会 2006 July 20-22
Flux penetration into RABiTS tape
YBCO(PLD)/CeO2/YSZ/CeO2/Ni
D. M. Feldmann (Polyanskii group) et al.
Appl. Phys. Lett. 77
(2000)2906.
15K 600 Oe
Rolling aligned Ni has a large
grain (~ 100µm).
Grain boundaries are connected each other with small angles,
and magnetic flux penetrates along grain boundaries.
Superconductivity Research Laboratory (SRL) - ISTEC
YBCO線材のMO法による評価
低温工学協会九州・西日本支部研究会 2006 July 20-22
素線評価
[NCCC]
RTR-MOI装置によるMO観察結果
IBAD/PLD (Total length 1.5m)
Ic~250A
ZFC 40K 80 mT
150 mm
10 mm
This tape has only a few defects. Magnetic flux penetration is uniform
for both width and length directions.
Suitable for scribing process
Superconductivity Research Laboratory (SRL) - ISTEC
低温工学協会九州・西日本支部研究会 2006 July 20-22
素線評価
YBCO線材のMO法による評価
Movie of the observation result by RTR-MOI
[NCCC]
Shooting time ~ 1 hour
IBAD/PLD (Total length 1.5m)
Ic ~250A
ZFC 40K 50 mT
Tape edge
10 mm
(width)
Tape edge
Superconductivity Research Laboratory (SRL) - ISTEC
低温工学協会九州・西日本支部研究会 2006 July 20-22
素線評価
YBCO線材のMO法による評価
Spatial resolution of RTR-MOI equipment
Both Hall sensor array equipment (tapestar@THEVA) and our new RTR-MOI can
visualize 2D-image of flux distribution.
Using same sample : TFA-MOD (Ic~100A) [SRL, early stage specimen]
40K, 50mT
10 mm
(width)
RTR-MOI
Hall sensor array
77K, 20mT
(Tapestar@THEVA)
There are many defects in this sample. Hall
sensors array can detect same defect.
1µm - 10µm
MOI has a higher spatial resolution !
Superconductivity Research Laboratory (SRL) - ISTEC
YBCO線材のMO法による評価
低温工学協会九州・西日本支部研究会 2006 July 20-22
Comparison with other characterization methods
Spatial resolution
Hall sensor array(Tapestar@THEVA)
1m
RTR MOI
Field
10m
coated conductor
Hall sensor array
system
100m
Moving
1mm
RTR I-V measurement
10mm
RTR I-V meas.
100mm
1m
1m
10m
100m
Measuring speed(m/h)
I
V
We must choose measuring method by the purpose!
Superconductivity Research Laboratory (SRL) - ISTEC

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