2012/09/16 by V. F. Kozhevnikov, Kozhevnikov, V., Andreas Suter +23
Physics and Astronomy · Engineering · #Physics of Superconductivity and Magnetism #Superconducting Materials and Applications #Superconductivity in MgB2 and Alloys
paper · pdf · doi:10.48550/arxiv.1209.3502
The Pippard coherence length ξ0 (the size of a Cooper pair) in an extreme type-I superconductor was determined directly through high-resolution measurement of the nonlocal electrodynamic effect combining low-energy muon spin rotation spectroscopy and polarized neutron reflectometry. The renormalization factor Z=mcp*/2m (mcp* and m are the mass of the Cooper pair and the electron, respectively) resulting from the electron-phonon interaction, and the temperature dependent London penetration depth λL(T) were determined as well. A general expression linking ξ0, Z and λL(0) is introduced and experimentally verified. This expression allows one to determine experimentally the Pippard coherence length in any superconductor, independent of whether the electrodynamics is local or nonlocal, conventional or unconventional.