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