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Critical behavior of vortices in epitaxial Tl‐2201 films at zero external field
Author(s) -
Chen H. Q.,
Johansson L.G.,
Ivanov Z. G.
Publication year - 2004
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200402094
Subject(s) - condensed matter physics , dissipation , flux (metallurgy) , physics , superconductivity , critical current , current (fluid) , vortex , resistive touchscreen , field (mathematics) , magnetic field , zero (linguistics) , critical field , transition temperature , magnetic flux , materials science , thermodynamics , electrical engineering , quantum mechanics , philosophy , mathematics , engineering , pure mathematics , metallurgy , linguistics
The resistive transition and current–voltage characteristics of a Tl‐2201 superconducting microbridge are measured close to the critical temperature in zero external magnetic field. The dissipation mechanism is studied by analyzing d V /d I and power dissipation P (= IV ) as functions of transport current. The J c – T curves exhibit three distinct types of behavior depending on temperature. In the low temperature regime, the critical current density is proportional to (1 – T / T c ). At intermediate temperatures, thermally activated flux creep dominates and J c is proportional to 1 – n ( T / T c ) – m ( T / T c ) 2 . In the high temperature regime, J c is equal to the G – L depairing current. The depinning current, J c 1 , is determined, taking into account thermally activated flux motion and flux motion induced by the transport current. J c 1 depends linearly on temperature and vanishes at 82 K, J c 1 = J c 1 (0) (1 – T / T c 1 ). (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)