Mühlbauer, S. ; Pfleiderer, C. ; Böni, P. ; Laver, M. ; Forgan, E.M. ; Fort, D. ; Keiderling, U. ; Behr, G.: Morphology of the superconducting vortex lattice in ultrapure niobium. Physical Review Letters 102 (2009), p. 136408/1-4
10.1103/PhysRevLett.102.136408
Abstract:
The morphology of the superconducting flux line lattice (FLL) of Nb comprises gradual variations with various lock-in transitions and symmetry breaking rotations. We report a comprehensive small-angle neutron scattering study of the FLL in an ultrapure single crystal of Nb as a function of the orientation of the applied magnetic field. We attribute the general morphology of the FLL and its orientation to three dominant mechanisms; first, nonlocal contributions, second, the transition between open and closed Fermi surface sheets and, third, the intermediate mixed state between the Meissner and the Shubnikov phase.