Resistive Transition of High-Temperature Superconductors

The model proposed recently by Yeshurun and Malozemoff to explain the "irreversibility line" in high-temperature superconductors is extended to account for the experimentally measured width and shape of the resistive transition in a magnetic field, without invoking material inhomogeneity. It is argues that high ${T}_{c}$ and ${H}_{c2}$ are necessary, but not sufficient, conditions for such materials to show zero resistance at room temperature in substantial magnetic fields.