Anomalous vortex dynamics in [kappa]-[bis(ethylenedithio)tetrathiafulvalene][sub 2]Cu[N(CN)[sub 2]]Br: Evidence for field-induced magnetic order and unconventional superconductivity

• Published in: Physical review. B, Condensed matter Condensed matter, 1995-02, Vol.51:5
• Main Authors: Lahaise, U.G.L., Chen, Q., De Long, L.E., Brock, C.P., Wang, H.H., Carlson, K.D., Schlueter, J.A., Williams, J.M.
• Format: Article
• Language: English
• Subjects: 665411 > Basic Superconductivity Studies-- (1992-); CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CRITICAL FIELD; FREQUENCY DEPENDENCE; FREQUENCY RANGE; HZ RANGE; MAGNETIC FIELDS; MAGNETIC FLUX; MAGNETIZATION; MATERIALS SCIENCE; ORGANIC SUPERCONDUCTORS; PHASE TRANSFORMATIONS; SUPERCONDUCTORS; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0000-0013 K; TEMPERATURE RANGE 0013-0065 K; TEMPERATURE RANGE 360607 > Other Materials-- Superconducting Properties-- (1992-)
• ISSN: 0163-1829; 1095-3795
• DOI: 10.1103/PhysRevB.51.3301

Anisotropic superconducting flux-line behavior of single-crystal [kappa]-[bis(ethylenedithio)tetrathiaful- valene][sub 2]Cu[N(CN)[sub 2]]Br has been studied with dc magnetization and vibrating-reed (VR) techniques. A peak at [ital T][sup *]([ital H]) in the temperature dependence of the VR inverse quality factor 1/[ital Q] exhibits a shoulder for magnetic fields 0[lt][mu][sub 0][ital H][le]0.5 T parallel to the conducting ac plane. The shoulder becomes unresolved near a kink in [ital T]*([ital H]) at [mu][sub 0][ital H][approx]0.7 T. Discontinuities in 1/[ital Q] and the VR frequency shift occur for 0.1[le][mu][sub 0][ital H][le]1.3 T applied perpendicular to the ac plane and temperatures [ital T][le]20 K, well into the normal state. These anomalies are preliminary evidence for a field-induced magnetic phase transition and unconventional superconductivity.