Sample size dependence of second magnetization peak in type-II superconductors

We show that the second magnetization peak (SMP), i.e., an increase in the magnetization hysteresis loop width in type-II superconductors, vanishes for samples smaller than a critical size. We argue that the SMP is not related to the critical current enhancement but can be well explained within a fr...

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Bibliographic Details
Published in:Tsinghua science and technology 2003-06, Vol.8 (3), p.370-378
Main Authors: Torres, J H S, Kopelevich, Y
Format: Article
Language:English
Online Access:Get full text
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Summary:We show that the second magnetization peak (SMP), i.e., an increase in the magnetization hysteresis loop width in type-II superconductors, vanishes for samples smaller than a critical size. We argue that the SMP is not related to the critical current enhancement but can be well explained within a framework of the thermomagnetic flux-jump instability theory, where flux jumps reduce the absolute irreversible magnetization relative to the isothermal critical state value at low enough magnetic fields. The recovering of the isothermal critical state with increasing field leads to the SMP. The low-field SMP takes place in both low-Tc conventional and high-Tc unconventional superconductors. Our results show that the restoration of the isothermal critical state is responsible for the SMP occurrence in both cases.
ISSN:1007-0214