MAGNETIZATION LOSSES IN HIGH TEMPERATURE … · 2. Annihilation losses: vortices of opposite...
Transcript of MAGNETIZATION LOSSES IN HIGH TEMPERATURE … · 2. Annihilation losses: vortices of opposite...
Institute of Low Temperatures and Structure ResearchPolish Academy of Science, Wroclaw, Poland
MAGNETIZATION LOSSES IN HIGH TEMPERATURE
SUPERCONDUCTING TAPES DUE
TO AC AND DC MAGNETIC FIELDS
Eduard Maievskyi, Marian Ciszek*
Division of Low Temperature and Superconductivity
*-also at Wrocław University of Technology
Eduard
Maievskyi
Institute of Low Temperatures and Structure ResearchPolish Academy of Science, Wroclaw, Poland
Outline
1. Application of superconducting materials
2. Object of studying
3. AC-losses
4. Experimental method and results
Marian
Ciszek
Institute of Low Temperatures and Structure ResearchPolish Academy of Science, Wroclaw, Poland
Application of Superconducting Materials
Eduard
Maievskyi
Marian
Ciszek
Institute of Low Temperatures and Structure ResearchPolish Academy of Science, Wroclaw, Poland
Cross-section of Sumitomo BSCCO-2223 composite tape type H
HTSC-tapes
Eduard
Maievskyi
Marian
Ciszek
Cross-section of SCS 4050 2G HTSC tape produced by SuperPower
Institute of Low Temperatures and Structure ResearchPolish Academy of Science, Wroclaw, Poland
HTSC-tapes
Eduard
Maievskyi
Marian
Ciszek
1. Bulk pinning losses:
2. Annihilation losses: vortices of opposite magnetic sense annihilate, one pair liberate energy
3. Surface losses: arising from a surface barrier
JEQb
rr⋅∝
012 φ⋅∝ ca HQ+Φο −Φο
Φ⋅∆∝ effs HQ
Institute of Low Temperatures and Structure ResearchPolish Academy of Science, Wroclaw, Poland
Main contributions to AC losses
Eduard
Maievskyi
Marian
Ciszek
Institute of Low Temperatures and Structure ResearchPolish Academy of Science, Wroclaw, Poland
Main contributions to AC losses
4. Flux flow losses: when pinning is very low;
2;
cnffffff B
BJE ⋅∝⋅∝ ρρρrr
5. In HTSC, additionally, contributions from -flux creep, granularity, anisotropy, grain boundaries
6. In composites: coupling between filaments,eddy currents in matrix
( )W f bff = 02 ,ω
Eduard
Maievskyi
Marian
Ciszek
Institute of Low Temperatures and Structure ResearchPolish Academy of Science, Wroclaw, Poland
Race-Track Coil
Eduard
Maievskyi
Marian
Ciszek
Institute of Low Temperatures and Structure ResearchPolish Academy of Science, Wroclaw, Poland
Measurement equipment
Eduard
Maievskyi
Marian
Ciszek
x
p/2
wHac
-I+I ( )
−= 2
2
0
2
2 wx
wIxB
πµ
( )
⋅= 22
1
xl
mxB
π
L
w
Φ( x=p/2)
p/2( )
p
mp
p
mpππ2
2 −=Φ⇒−=
Φ
"
2 rmsrmsVHLf
pP
π=
t
m
ptV
∂∂=
π2
)(
( ) tmtmtm ωω sincos ′′+′= ( )ωπ
2)(
ptVtm
′′=′′
( ) dtt
mtH
LdmH
LP
T
∂∂== ∫∫
0
11
M Iwakuma,.. SUST 16 (2003) 545
D N Nguyen,...SUST 19 (2006) 1010
Y Yang,...J. App. Phys. 96 (2004) 2141
Loop has to be extended from the edge of a tape
Institute of Low Temperatures and Structure ResearchPolish Academy of Science, Wroclaw, Poland
Measurement equipment
Eduard
Maievskyi
Marian
Ciszek
Institute of Low Temperatures and Structure ResearchPolish Academy of Science, Wroclaw, Poland
Eduard
Maievskyi
Marian
Ciszek
Energy dissipation in BSCCO-2223 tape AC-field only
Institute of Low Temperatures and Structure ResearchPolish Academy of Science, Wroclaw, Poland
Energy dissipation in YBCO-123 tape (AC-field only)
Eduard
Maievskyi
Marian
Ciszek
Institute of Low Temperatures and Structure ResearchPolish Academy of Science, Wroclaw, Poland
Energy dissipation in YBCO-123 tape (AC-field only)
∂∂−
∂∂−=
z
H
x
HJ xz
ywhen d<<a
( ) ( ) ( )[ ]2/,2/,4
dzxBdzxBd
cxJ xxy −=−=−=
π
−= )tanh()cosh(ln21
)( xxxx
xg40
2 baQm ∝
02baIQ cm ∝
( )xJ y
( )xBz
cBbx 0= aIB cc πµ 20=
( )xgbaQm ⋅= 20
2
0
4µπ
parametr x=b0/Bc
0.1 1 10 100
func
tion
g(x)
10-3
10-2
10-1
100
E.H. Brandt and M. Indenbom, PRB 48 (1993) 12893
J.R. Clem, E. Zeldov, PRB 49 (1994) 9802.
Loss model for a thin film (perpendicular field)
Eduard
Maievskyi
Marian
Ciszek
Institute of Low Temperatures and Structure ResearchPolish Academy of Science, Wroclaw, Poland
Energy dissipation in YBCO-123 tape (AC-field only)
Eduard
Maievskyi
Marian
Ciszek
Institute of Low Temperatures and Structure ResearchPolish Academy of Science, Wroclaw, Poland
Hysteretic loss minimum in BSCCO-2223 tape
Eduard
Maievskyi
Marian
Ciszek
Institute of Low Temperatures and Structure ResearchPolish Academy of Science, Wroclaw, Poland
Hysteretic loss minimum in YBCO-123 tape
Eduard
Maievskyi
Marian
Ciszek
Institute of Low Temperatures and Structure ResearchPolish Academy of Science, Wroclaw, Poland
Clem model
�`�- total losses
�`�- surface losses
�`��- bulk pinning losses
�`��- bulk annihilation losses
John R. Clem, „Theory of AC losses in type II superconductors with a field-dependent surface barier”,
J. Appl. Phys. 50(5), May 1979
Eduard
Maievskyi
Marian
Ciszek
g{tÇ~ çÉâ yÉÜ tààxÇà|ÉÇ 4
Institute of Low Temperatures and Structure ResearchPolish Academy of Science, Wroclaw, Poland
Eduard
Maievskyi
Marian
Ciszek