vortex phase diagram
Springer Online Journal Archives 1860-2000
Electrical Engineering, Measurement and Control Technology
Abstract Investigations on flux dynamics of ring-shaped T12Ba2CaCu2O8 superconducting thin films have been carried out by measuring the temperature dependent magnetization M(T) during field-cooling (FC) and zero-field-cooling (ZFC) processes. For a given magnetic field, from the magnetization behavior two distinct temperatures, Tkink and Tirr, can be defined. Below Tkink, a clear hysteretic behavior of M(T) is observed leading to a large irreversible signal ΔM = MFC − MZFC. Above Tkink, this irreversible signal, though being very small, is still non-zero until it eventually vanishes at a higher temperature Tirr. Above Tirr, both curves MFC(T) and MZFC(T) merge together and become temperature independent. We attribute the first region ( T〈 Tkink) to a 3D vortex-glass phase, the second region (Tkink 〈 T 〈 Tirr) to a vortex line liquid state and the third region (Tirr 〈 T 〈 Tc) to a pancake liquid state.
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