Download pdf - MAGNETIZATION LOSSES IN HIGH TEMPERATURE … · 2. Annihilation losses: vortices of opposite magnetic sense annihilate, one pair liberate energy 3. Surface losses: arising from a

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


Outline

1. Application of superconducting materials

2. Object of studying

3. AC-losses

4. Experimental method and results

Marian

Ciszek


Application of Superconducting Materials

Eduard

Maievskyi

Marian

Ciszek


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


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


Main contributions to AC losses

Eduard

Maievskyi

Marian

Ciszek


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


Race-Track Coil

Eduard

Maievskyi

Marian

Ciszek


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


Measurement equipment

Eduard

Maievskyi

Marian

Ciszek


Eduard

Maievskyi

Marian

Ciszek

Energy dissipation in BSCCO-2223 tape AC-field only


Energy dissipation in YBCO-123 tape (AC-field only)

Eduard

Maievskyi

Marian

Ciszek



∂∂−

∂∂−=

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



Eduard

Maievskyi

Marian

Ciszek


Hysteretic loss minimum in BSCCO-2223 tape

Eduard

Maievskyi

Marian

Ciszek


Hysteretic loss minimum in YBCO-123 tape

Eduard

Maievskyi

Marian

Ciszek


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


Eduard

Maievskyi

Marian

Ciszek