91 research outputs found
Double-stage continuous-discontinuous superconducting phase transition in the Pauli paramagnetic limit of a 3D superconductor: the URuSi case
The sharp suppression of the de-Haas van-Alphen oscillations observed in the
mixed superconducting (SC) state of the heavy fermion compound URuSi is shown to confirm a theoretical prediction of a narrow double-stage SC
phase transition, smeared by fluctuations, in a 3D paramagnetically-limitted
superconductor. The predicted scenario of a second order transition to a
nonuniform (FFLO) state followed by a first order transition to a uniform SC
state, obtained by using a non-perturbative approach, is also found to be
consistent with recent thermal conductivity measurements performed on this
material.Comment: 4 pages, 3 figure
Damping of dHvA oscillations and vortex-lattice disorder in the peak-effect region of strong type-II superconductors
The phenomenon of magnetic quantum oscillations in the superconducting state
poses several questions that still defy satisfactory answers. A key
controversial issue concerns the additional damping observed in the vortex
state. Here, we show results of \mu SR, dHvA, and SQUID magnetization
measurements on borocarbide superconductors, indicating that a sharp drop
observed in the dHvA amplitude just below H_{c2} is correlated with enhanced
disorder of the vortex lattice in the peak-effect region, which significantly
enhances quasiparticle scattering by the pair potential.Comment: 4 pages 4 figure
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