Abstract
In the early, heady days of high-temperature superconductivity, researchers searched around the clock for the slightest decrease in the resistance of their samples that might indicate a newer, higher-temperature superconductor. The fact that these materials were poor conductors – 100 times worse than copper at room temperature – and that, in an applied magnetic field, the resistance in the "superconducting" state only dropped very gradually were of secondary concern (figure 1).