Hanson, H.A.; Wang, X.; Dimitrov, I.K.; Shi, J.; Ling, X.S.; Maranville, B.B.; Majkrzak, C.F.; Laver, M.; Keiderling, U.; Russina, M.: Structural evidence for an edge-contaminated vortex phase in a Nb crystal using neutron diffraction. Physical Review B 84 (2011), p. 014506/1-7
DOI version (server of publisher)
We report the structural observation of a disordered vortex matter phase existing near the edge of a bulk type-II superconductor Nb using a novel position-sensitive neutron diffraction technique. This “edge-contaminated” vortex state was implicated in previous studies using transport techniques and magneto-optics and is postulated to play a significant role in the behavior of vortex dynamics in a wide range of type-II superconductors. In this sample, thermal annealing causes the vortex matter in the interior to reorder implying that the edge-contaminated bulk state is metastable. However, the edge vortex structure remains disordered after repeated thermal annealing indicating the spatial coexistence of a vortex glass with a Bragg glass. This observation resolves outstanding issues concerning the peak effect in type-II superconductors.