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Peak effect in optimally doped p-type single-crystal Ba0.5K0.5Fe2As2 studied by ac magnetization measurements
Journal Contribution - Journal Article
We have used the ac magnetic susceptibility to investigate the vortex state in an optimally doped p-type Ba0.5K0.5Fe 2As2 single crystal under various ac and dc fields. A peak effect is observed in the temperature dependence of the in-phase ac susceptibility, indicating an order-disorder transition on the vortex phase diagram. The peak effect displays an anomalous history effect compared with other type-II superconductors, which we ascribe to the strong pinning existing in the material. We observe the development of a small dissipation peak at the temperature Tp2 slightly below the peak effect region. Similar to the peak effect boundary, Tp2 delimits a region in the H-T phase diagram which is independent on the ac field amplitude. We argue that this small peak may arise from the softening of the vortex lattice, leading to a collective pinning of the whole vortex lattice. This effect assists and further enhances the peak effect occurring in the Ba0.5K0.5Fe 2As2 superconductor. © 2013 American Physical Society.
Journal: Physical Review B
ISSN: 2469-9950
Issue: 14
Volume: 88
Publication year:2013
BOF-keylabel:yes
IOF-keylabel:yes
BOF-publication weight:1
CSS-citation score:1
Authors:International
Authors from:Higher Education
Accessibility:Open