Thermodynamic and Transport Measurements on Superconducting NaxCoO2 + yH2O Single Crystals Prepared by Electrochemical De-intercalation
Abstract
Superconducting single crystal samples of NaxCoO2 + yH2O have been produced using an electrochemical technique which dispenses with the usual bromine chemical de-intercalation step and permits much more precise control of the Na content. After careful hydration, nearly single-phase crystals have been obtained in which over 90% of the sample's volume corresponds to the superconducting Na0.3CoO2 + 1.3H2O structure. Susceptibility and specific heat measurements confirm that bulk superconductivity has been achieved. The extracted normal state density of states indicates Fermi-liquid behavior with strong mass enhancement and a modest Wilson ratio. Measurements of Hc2 for H||c and H||ab reveal significant anisotropy. The estimated value of Hc2 for H||c yields a coherence length of ~100 A, consistent with an extremely narrow bandwidth.
Turn this paper into a full lesson
ArcXiv compiles a staged curriculum from this paper: 8-12 lessons across beginner → advanced, synthesised section guides, visuals, flashcards, a quiz, exercises, and on-demand deep dives per section. Grounded in the abstract, never invented.