Cuprate superconductivity: a ceramic changed the temperature scale

The first report deliberately said possible

Bednorz and Müller’s 1986 report described possible high-temperature superconductivity in barium–lanthanum–copper oxides. Resistance dropped at unexpectedly high temperatures for the known superconductors of the time.

Ceramic samples could contain several phases and inhomogeneous current paths. Reproduction, magnetic tests and identification of the responsible phase made the case stronger than the first resistance anomaly alone.

Sources: [3][1]

Zero resistance and magnetic screening complement each other

A connected superconducting path can reduce the measured voltage even when only part of a sample participates. Magnetic screening and thermodynamic measurements probe other aspects of the superconducting volume and state. Sample geometry and granularity still matter.

Sources: [1]

A discovery did not settle the microscopic mechanism

The 1987 award recognized the discovery of superconductivity in ceramic materials. Establishing that state is distinct from proving a complete microscopic explanation for the pairing interaction. A familiar weak-coupling formula cannot simply be assumed to predict the cuprates.

Sources: [1][2]

The critical-field model supplies a limited comparison

The new critical-field Lab uses an isotropic near-transition description to explain flux entry and destruction of order. It does not identify the high-temperature mechanism or recreate a measured cuprate phase diagram. The crossover Lab likewise provides pairing concepts, not a material-specific solution.

Sources: [1][4][5]