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• 1. [Article] Coherent vs Incoherent Interlayer Transport in Layered Metals

  The magnetic-field, temperature, and angular dependence of the interlayer magnetoresistance of two different quasi-two-dimensional (2D) organic superconductors is reported. For k -BEDT-TTF)₂I₃, where BEDTTTF ...

  Citation × Citation Citation Abstract Copy Title: Coherent vs Incoherent Interlayer Transport in Layered Metals Author: Gard, Gary L., Wosnitza, J., Hagel, J., Qualls, J. S., Brooks, J. S., Balthes, E., Schweitzer, D., Schlueter, J. A., Geiser, U., Mohtasham, Javid, Winter, Rolf Walter Year: 2002 The magnetic-field, temperature, and angular dependence of the interlayer magnetoresistance of two different quasi-two-dimensional (2D) organic superconductors is reported. For k -BEDT-TTF)₂I₃, where BEDTTTF is bisethylenedithio-tetrathiafulvalene, we find a well-resolved peak in the angle-dependent magnetoresistance at Q590°(field parallel to the layers). This clear-cut proof for the coherent nature of the interlayer transport is absent for β″–(BEDT-TTF)₂SF₅CH₂CF₂SO₃. This and the nonmetallic behavior of the magnetoresistance suggest an incoherent quasiparticle motion for the latter 2D metal. Title: Coherent vs Incoherent Interlayer Transport in Layered Metals Author: Gard, Gary L., Wosnitza, J., Hagel, J., Qualls, J. S., Brooks, J. S., Balthes, E., Schweitzer, D., Schlueter, J. A., Geiser, U., Mohtasham, Javid, Winter, Rolf Walter Year: 2002 The magnetic-field, temperature, and angular dependence of the interlayer magnetoresistance of two different quasi-two-dimensional (2D) organic superconductors is reported. For k -BEDT-TTF)₂I₃, where BEDTTTF is bisethylenedithio-tetrathiafulvalene, we find a well-resolved peak in the angle-dependent magnetoresistance at Q590°(field parallel to the layers). This clear-cut proof for the coherent nature of the interlayer transport is absent for β″–(BEDT-TTF)₂SF₅CH₂CF₂SO₃. This and the nonmetallic behavior of the magnetoresistance suggest an incoherent quasiparticle motion for the latter 2D metal. Close

• 2. [Article] Enhanced magnetic quantum oscillations in the mixed state of a two-dimensional organic superconductor

  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 ...

  Citation × Citation Citation Abstract Copy Title: Enhanced magnetic quantum oscillations in the mixed state of a two-dimensional organic superconductor Author: Wosnitza, J., Hagel, J., Meeson, P. J., Bintley, D., Schlueter, J. A., Mohtasham, Javid, Winter, Rolf Walter, Gard, Gary L. Year: 2003 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. Title: Enhanced magnetic quantum oscillations in the mixed state of a two-dimensional organic superconductor Author: Wosnitza, J., Hagel, J., Meeson, P. J., Bintley, D., Schlueter, J. A., Mohtasham, Javid, Winter, Rolf Walter, Gard, Gary L. Year: 2003 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. Close

• 3. [Article] Fermiology and superconductivity at high magnetic fields in a completely organic cation radical salt

  We report specialized interplane magnetoresistance (MR) measurements on the organic superconducting compound β″–(BEDT-TTF)₂SF₅CH₂CF₂SO₃ (where BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene) in both ...

  Citation × Citation Citation Abstract Copy Title: Fermiology and superconductivity at high magnetic fields in a completely organic cation radical salt Author: Brooks, J. S., Williams, V., Choi, E., Graf, D., Tokumoto, M., Uji, S., Zuo, F., Wosnitza, J., Schlueter, J. A., David, H., Winter, Rolf Walter, Gard, Gary L., Storr, K. Year: 2006 We report specialized interplane magnetoresistance (MR) measurements on the organic superconducting compound β″–(BEDT-TTF)₂SF₅CH₂CF₂SO₃ (where BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene) in both the superconducting (Tc ∼ 5K) and normal states versus magnetic field direction. In the normal state, detailed angular-dependent magnetoresistance oscillation (AMRO) studies reveal peculiar features of the Fermi surface topology of this compound, and very high magnetic field studies further support the unusual nature of the electronic structure. In the superconducting state we investigate, through detailedAMRO measurements, the anomalous MR peak that appears within the superconducting field-temperature phase diagram. Our results reveal a direct connection between the superconducting state determined from purely in-plane field, and the vortex lattice produced by the inter-plane magnetic field. We also describe several unique sample rotation instruments used in these high field experiments, including the use of dysprosium pole pieces in combination with a 45 T hybrid magnet to carry out measurements at the highest steady-state resistive magnetic field (47.8 T) yet achieved. Title: Fermiology and superconductivity at high magnetic fields in a completely organic cation radical salt Author: Brooks, J. S., Williams, V., Choi, E., Graf, D., Tokumoto, M., Uji, S., Zuo, F., Wosnitza, J., Schlueter, J. A., David, H., Winter, Rolf Walter, Gard, Gary L., Storr, K. Year: 2006 We report specialized interplane magnetoresistance (MR) measurements on the organic superconducting compound β″–(BEDT-TTF)₂SF₅CH₂CF₂SO₃ (where BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene) in both the superconducting (Tc ∼ 5K) and normal states versus magnetic field direction. In the normal state, detailed angular-dependent magnetoresistance oscillation (AMRO) studies reveal peculiar features of the Fermi surface topology of this compound, and very high magnetic field studies further support the unusual nature of the electronic structure. In the superconducting state we investigate, through detailedAMRO measurements, the anomalous MR peak that appears within the superconducting field-temperature phase diagram. Our results reveal a direct connection between the superconducting state determined from purely in-plane field, and the vortex lattice produced by the inter-plane magnetic field. We also describe several unique sample rotation instruments used in these high field experiments, including the use of dysprosium pole pieces in combination with a 45 T hybrid magnet to carry out measurements at the highest steady-state resistive magnetic field (47.8 T) yet achieved. Close