場 所：工６号館 １階 大会議室
講演者：Prof. V.V. Moshchalkov (INPAC-Institute for Nanoscale Physics and Chemistry,
Katholieke Universiteit Leuven)
題 目：Type-1.5 Superconductivity (*)
The existence of the novel superconducting state has been demonstrated in two-component high quality MgB2 single crystalline superconductors where a unique combination of both type-1 and type-2 conditions is realized in a single material: λ1/ξ1<1/√2 for the first component of the order parameter and λ2/ξ2>1/√2 for the second one. Such materials are, in fact, type-1.5 superconductors (PRL 102, 117001 (2009)), since they combine simultaneously both type-1 and type-2 superconductivity. This leads to a drastic change in the vortex-vortex interaction, which results in the appearance of stable vortex stripes, clusters and gossamer-like vortex patterns. We have directly visualized these novel patterns by using Bitter decoration and scanning SQUID microscopy. The observed patterns are in a good agreement with the molecular dynamics simulations based on the vortex-vortex interaction corresponding to the type-1.5 superconductivity.
(*) In collaboration with: A.V. Silhanek, W. Gillijns, J. Van de Vondel, M. Menghini, J. Fritzsche, R. Kramer, T. Nishio, Q.H. Chen, V. H. Dao, L. F. Chibotaru, N. D. Zhigadlo, J. Karpinski, and V. Metlushko