2008/06/08 by X. L. Wang, S. R. Ghorbani, Wang, X. L. +15
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Iron-based superconductors research #Physics of Superconductivity and Magnetism #Rare-earth and actinide compounds #Superconductivity (cond-mat.supr-con) #cond-mat.supr-con
paper · pdf · doi:10.48550/arxiv.0806.1318
4 pages, 6 figures. submitted on 8 June 2008
arxiv created 2008/06/08 · openalex publication_date 2008/06/08 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The flux pinning mechanism of NdO0.82F0.18FeAs superconductor made under high pressure, with a critical temperature, Tc, of 51 K, has been investigated in detail in this work. The field dependence of the magnetization and the temperature dependence of the magnetoresistivity were measured in fields up to 13 T. The field dependence of the critical current density, Jc(B), was analyzed within the collective pinning model. A crossover field, Bsb, from the single vortex to the small vortex bundle pinning regime was observed. The temperature dependence of Bsb(T) is in good agreement with the delta-l pinning mechanism, i.e., pinning associated with fluctuations in the charge-carrier mean free path, l. Analysis of resistive transition broadening revealed that thermally activated flux flow is found to be responsible for the resistivity contribution in the vicinity of Tc. The activation energy U0/kB is 2000 K in low fields and scales as B (-1/3) over a wide field range. Our results indicate that the NdO0.82F0.18FeAs has stronger intrinsic pinning than Bi-2212 and also stronger than MgB2 for H > 8 T.