Dresden 2009 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 27: Superconductivity: Vortex Dynamics, Vortex Phases, Pinning

TT 27.2: Vortrag

Mittwoch, 25. März 2009, 14:15–14:30, HSZ 105

Intrinsic bulk vortex lattice dynamics and tilt moduli revealed by time resolved small angle neutron scattering. — •Sebastian Mühlbauer^1,2, Christian Pfleiderer¹, Peter Böni¹, Albrecht Wiedenmann³, Ted Forgan⁴, and Günter Behr⁵ — ¹Physik Department E21, Technische Universität München, D-85748 Garching — ²Forschungsneutronenquelle Heinz Maier-Leibnitz, FRM II, D-85748 Garching — ³Institut Laue Langevin, ILL, Grenoble, France — ⁴School of Physics and Astronomy, University of Birmingham, Birmingham UK — ⁵IFW Dresden, D-01069 Dresden,

In contrast to the local elasticity of crystal lattices, the elasticity of Vortex Lattices (VL) in superconductors is of non-local origin. The VL elasticity, thermal stability, pinning and transport properties can be described by the temperature, field and k-dependent elastic moduli c₁₁, c₄₄ and c₆₆, hence yielding important informations on the microscopic nature of superconductivity. Measurements of the VL elastic moduli are traditionally limited to macroscopic transport measurements on bulk samples or microscopic surface sensitive methods such as decoration techniques. We report on a new method to measure the VL tilt modulus c₄₄ by means of stroboscopic small angle neutron scattering, combined with a time varying magnetic field setup on an ultrapure niobium single crystal with vanishing pinning. This method allows the microscopic determination of the intrinsic VL elastic moduli in large bulk samples, unhampered by surface effects. We present first data, showing a clear change of the vortex-vortex interaction at the transition from the intermediate mixed state to the mixed state.