Matthias rules

In physics, the Matthias rules refers to a historical set of empirical guidelines on how to find superconductors.

Superconductivity was first discovered in solid mercury in 1911 by Heike Kamerlingh Onnes and Gilles Holst, who had developed new techniques to reach near-absolute zero temperatures.

[1][2][3] In subsequent decades, superconductivity was found in several other materials; In 1913, lead at 7 K, in 1930's niobium at 10 K, and in 1941 niobium nitride at 16 K. In 1933, Walther Meissner and Robert Ochsenfeld discovered that superconductors expelled applied magnetic fields, a phenomenon that has come to be known as the Meissner effect.

Bernd T. Matthias and John Kenneth Hulm were encouraged by Enrico Fermi to start a systematic experimental investigation in the 1950s, looking for superconductors in different elements and compounds.

[11] Geballe and Matthias won the Oliver E. Buckley Condensed Matter Prize in 1970 for "For their joint experimental investigations of superconductivity which have challenged theoretical understanding and opened up the technology of high field superconductors.

Bernd T. Matthias (left) points to the element niobium on the periodic table while John Eugene Kunzler looks on. After reporting to the American Physical Society that a ductile alloy of niobium and zirconium will remain superconducting at liquid helium temperature.