We have prepared and identified as a single phase the high-temperature superconducting compound in the chemical system Y-Ba-Cu-O, an orthorhombic, distorted oxygen-deficient perovskite of stoichiometry ${\mathrm{Ba}}_2$${\mathrm{YCu}}_3$${\mathrm{O}}_{9\mathrm{-}\mathrm{\delta }}$ (δ≃2.1). Samples exhibit zero resistance at 91 K, with a transition width of 1.5 K. The Meissner effect attains a value of 76% of the independently measured diamagnetic susceptibility. We estimate parameters that characterize this superconductor, e.g., γ≃3–5 mJ (mole Cu${)}^{\mathrm{-}1}$ ${\mathrm{K}}^{\mathrm{-}2}$. The critical current density at 77 K and H=0 exceeds 1100 A/${\mathrm{cm}}^2$.

• Received 5 March 1987

DOI:https://doi.org/10.1103/PhysRevLett.58.1676

This article appears in the following collection:

Heating up of Superconductors

This collection marks the 30th anniversary of the discovery of high-temperature superconductors. The papers selected highlight some of the advances that have been made to date, both in understanding why these compounds behave in the way they do, and in utilizing them in applications.