Quantum spin dynamics

Abstract:

The magnetic behaviour and resistivity of single crystals of the layered organic superconductor, kappa-(BEDT-TTF)(2)Cu(NCS)(2), have been studied as a function of the orientation of the applied magnetic field. When the magnetic held lies in the quasi-two-dimensional planes of the material, there is strong evidence for a phase transition from the superconducting state into a Fulde-Ferrell-Larkin-Ovchinnikov state. (C) 2001 Elsevier Science B.V. All rights reserved.

Abstract:

An angle-dependent study of the magneto-optical response of the p-wave triplet-paired perovskite superconductor Sr2RuO4\ reveals several new cyclotron resonance effects. We observe an odd-harmonic cyclotron resonance series, probably arising from the gamma Fermi surface, with a fundamental cyclotron mass of 12.6 m(e). In addition, we find several resonance branches which behave in unconventional ways owing to the unusual nature of the band dispersion in this material. The results confirm the complexity of the Sr2RuO4 Fermi surface topology and show that earlier conclusions drawn from millimetre-wave experiments should be reconsidered. (C) 2001 Elsevier Science B.V. All rights reserved.