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LES PROPRIETES PARTICULIERES DES RUBANS SUPRACONDUCTEURS P.Bernstein 1 , Y.Thimont 1 and C.McLoughlin 1,2 1 CRISMAT (UMR-CNRS 6508) -ENSICAEN and Université de Caen-Basse Normandie, Boulevard du Maréchal Juin F14050 Caen cedex, France
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LES PROPRIETES PARTICULIERES DES RUBANS SUPRACONDUCTEURS P.Bernstein1,Y.Thimont1 and C.McLoughlin1,2 1 CRISMAT (UMR-CNRS 6508) -ENSICAEN and Université de Caen-Basse Normandie, Boulevard du Maréchal Juin F14050 Caen cedex, France 2National Centre for Plasma Science and Technology, School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9, Ireland
COATED CONDUCTORS (2G HTS TAPES) YBa2Cu3O7-d (YBCO) FAMILY
SUPERCONDUCTING TRANSFORMERS P=63MVA
Superconducting Magnetic Energy Storage (SMES) V=5dm3 E (kJ)
LES PROPRIETES PARTICULIERES DES RUBANS SUPRACONDUCTEURS • La densité de courant critique et l’existence d’un possible gradient de température critique • Le comportement au-delà du courant critique
La densité de courant critique et l’existence d’un possible gradient de température critique
SuperPower SF4050 NbN M.E.Gershenzon and V.N.Gubankov Pi’sma Zh.Eksp.Teor.Fiz 32, 236 (1980)
La densité de courant critique et l’existence d’un possible gradient de température critique • La mesure magnétique de la densité de courant critique en fonction de la température • Comparaison entre des rubans de différents fabricants • Détermination de la distribution de Tc le long de la profondeur des films
L L L w w w d d d 1 2 3 4 L w d SQUID magnetic moment measurement 5
Surface Critical Current Determination L w * * E.H.Brandt and M.Indenbom, Phys.Rev.B48, 12893 (1993) *Critical Current Measurement in HTS YBaCuO ribbons, Th.Lécrevisse et al. ASC2010
MEASURED COATED CONDUCTORS • 1 - American Superconductor • 2 – SuperPower • 3 - Theva
COMPARISON WITH THE SURFACE CRITICAL CURRENT DENSITY AT LOW TEMPERATURE (Tmin) OF NOWADAYS COATED CONDUCTORS
c { Z1 Tc1 { Z2 Tc2 { Zn Tcn SUBSTRATE IS THERE A Tc PROFILE ALONG THE THICKNESS OF THE FILMS?
Transactions on Superconductivity 19, 3541 (2009) EUCAS-Dresden Sept.2009, Journal of Physics Conference serie 234, 012003 (2010)
YBCO FILMS INCLUDE GENERALLY A LARGE NUMBER OF BOUNDARY PLANES (TWIN BOUNDARIES OR LOW ANGLE GRAIN BOUNDARIES)… JP Contour et al. Thin Solid Films 319, 211 (1998)
d2 …THAT INCLUDE JOSEPHSON WEAK LINKS strains, atomic defects or displacements, vacancies…. xab weak link tunneling current d1 xab : coherence length
c axis d [110] …IN Z SUPERIMPOSED ROWS twin boundary Z Tunneling current P. Bernstein, J.F. Hamet and Y. Thimont PhysicaC468, 200 (2008)
CRITICAL SURFACE CURRENT DENSITY: COATED CONDUCTORS if if
WEAK LINKS ROWS WITH DIFFERENT Tc ? c { c axis Z1 Tc1 { Z2 Tc2 { Zn Tcn [110] SUBSTRATE { if if
MICROWAVE ANNEALING of a YBCO/STO FILM AT PO2=500mbar cumulated micro-wave energy
MICROWAVE ANNEALING of a YBCO/STO FILM at PO2=500mbar d1 : thickness of the high Tc domain
oxygen MICROWAVE ANNEALING: OXYGEN DEPLETION and REDISTRIBUTION in the TWIN and GRAIN BOUNDARIES ? c axis
SUMMARY and CONCLUSIONS • The supposition that the JScr(T) behavior is governed by the current flow in the twin and grain boundaries is consistent with the shape of the JScr(T) curve and the existence of a Tc gradient along the c –axis of the films. • The superconducting thickness can be different from the deposited thickness and depends probably on the oxygen distribution in the films twin and grain boundaries • We have proposed a simple method to determine JScr from T=0K to Tc • The current carried at 77K depends at first on the width of the high Tc zone in the film.
INVESTIGATION of POWER DISSIPATION MECHANISMS in COATED CONDUCTORS at HIGH CURRENT DENSITIES BASED on ULTRA-FAST PULSED CURRENT MEASUREMENTS P.Bernstein, C.McLoughlin,Y.Thimont CRISMAT-ENSICAEN (UMR CNRS 6508) – Caen FRANCE F.Sirois and J.Coulombe Ecole Polytechnique de Montréal - Montréal CANADA
I Rmetal RYBCO METALLIC LAYER : ELECTRICAL SHUNT + HEAT SINK ? INVESTIGATION of the INTRINSIC PHYSICAL PROCESSES OCCURRING within the SUPERCONDUCTING FILMS and the METALLIC LAYERS WHEN an OVERCRITICAL CURRENT FLOWS in CCs
OUTLINE PULSED CURRENT MEASUREMENTS THE FLUX FLOW REGIME THE OHMIC REGIME CONCLUSIONS
PULSED CURRENT MEASUREMENTS THERMAL EFFECTS OF THE OVERCRITICAL CURRENTS J.Maza et al. Phys.Rev B78 094512 (2008) 3-10ms RISE TIME Currents up to 1000 A (i.e. 10 x Ic) ! « Characterization of electrical resistance of HTS coated conductors at high currents using ultra-fast regulated current pulses » F. Sirois et al. SuST 23(3) 034018 (2010)
OHMIC FLUX FLOW FLUX CREEP OHMIC FLUX FLOW MEASUREMENTS AT 77K FLUX CREEP