Part of this work was supported by the ESF Scientific Program on Fermi-liquid instabilities in correlated metals (FERLIN), by the DFG, and by the TMR program under contract No. ERBFMGECT950077. Work at Argonne National Laboratory was supported by the U.S. Department of Energy (Grant No. W-31-109-ENG-38). Work at Portland State University was supported by NSF (Grant No. Che- 9904316) and the Petroleum Research Fund (ACS-PRF Grant No. 34624-AC7).
Physical Review B
Organic superconductors, Magnetometers, Superconductors -- Evaluation, Scattering -- Physics
We report on de Haas–van Alphen (dHvA) oscillations observed in the mixed state of the organic superconductor β″–(BEDT-TTF)₂SF₅CH₂CF₂SO₃ (BEDT-TTF stands for bisethylenedithio-tetrathiafulvalene) utilizing the field-modulation technique and torque magnetometry. At low temperatures (30 mK), the dHvA signal persists down to 1.4 T well below the upper critical field Bc2≈3.6T. Contrary to most theoretical predictions and previous experimental findings, no additional damping of the dHvA-oscillation amplitude, but a reduced damping of the dHvA signal is found. This highly unusual effect might indicate a reduced quasiparticle scattering rate or an additional oscillatory contribution in the superconducting state.
J. Wosnitza, J. Hagel, P.J. Meeson, J.A. Schlueter, J. Mohtasham and R. W. Winter, "Enhanced Magnetic Quantum Oscillations in the Mixed State of a Two-Dimensional Organic Superconductor," Phys. Rev. B, 67, 060504-1 (2003).