1. Intergrain effects in the AC susceptibility of polycrystalline LaFeAsO_{0.94}F_{0.06}: comparison with cuprate superconductors
- Author
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Bonsignore, G., Vigni, A. Agliolo Gallitto M. Li, Luo, J. L., Chen, G. F., Wang, N. L., and Shovkun, D. V.
- Subjects
Condensed Matter - Superconductivity - Abstract
The AC susceptibility at zero DC magnetic field of a polycrystalline sample of LaFeAsO_{0.94}F_{0.06} (T_c = 24 K) has been investigated as a function of the temperature, the amplitude of the AC magnetic field (in the range Hac = 0.003 - 4 Oe) and the frequency (in the range f = 10 kHz - 100 kHz). The temperature dependence of the AC susceptibility exhibits the typical two-step transition arising from the combined response of superconduncting grains and intergranular weak-coupled medium. The intergranular part of the susceptibility strongly depends on both the amplitude and the frequency of the AC driving field, from few Kelvin below T_c down to T = 4.2 K. Our results show that, in the investigated sample, the intergrain critical current is not determined by pinning of Josephson vortices but by Josephson critical current across neighboring grains., Comment: 12 pages, 6 embedded figures, submitted for publication in Supercond. Sci. Technol
- Published
- 2010
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