The disappointing story of superconductivity in Strontium Ruthenate

In 1994 superconductivity was discovered in strontium ruthenate (Sr2RuO4). This attracted considerable interest because it had a perovskite crystal structure , just like the cuprates. Furthermore, it was a stoichiometric compound and so not plagued by impurities like the cuprates. In 1998, things got more interesting when NMR Knight shift measurements were interpreted as evidence for triplet…