MIDIT OFD CATS Modelling, Nonlinear Dynamics Optics and Fluid Dynamics Chaos and Turbulence Studies and Irreversible Thermodynamics Risø National Laboratory Niels Bohr Institute and Technical University of Denmark Building 128 Department of Chemistry Building 321 P.O. Box 49 University of Copenhagen DK-2800 Lyngby DK-4000 Roskilde DK-2100 Copenhagen Ø Denmark Denmark Denmark
Verner K. Thorsmolle
Los Alamos National Laboratory,
S K 763, Los Alamos, NM 87545
Wednesday, September 12, 2001, 14:00 h
at IMM, Bldg. 305, Room 018, DTU
We are presenting the first measurements of the JPR in high-Tc superconductor as a function of temperature and magnetic field employing THz-TDS in transmission and directly measured in the time-domain. Using this technique we find evidence for a linelike structure of the liquid phase in Tl-2212 above the calculated melting transition. YBCO with anisotropy ~8 has a liquid phase of vortex lines, while Bi-2212 with anisotropy ~600 has a liquid phase of pancake vortices. The anisotropy is defined as \u03B3=?c/?ab (c-axis penetration depth over ab-plane penetration depth). It is a surprising result that Tl-2212 behaves as YBCO in this respect despite the closer anisotropy (~150) to Bi-2212.