High-temperature superconductivity and electron paramagnetic resonance spectroscopy

Abstract

A brief discussion of superconductivity is presented, with special reference to the new, high-temperature superconductors. The latter are ternary or quaternary ionic oxides (ceramics) whose key component is Cu²⁺. However, the characteristic EPR spectrum of Cu²⁺ is not observed in these superconductors, except as the result of the presence of certain impurities. The reasons for this EPR-silence are discussed, and the usefulness of EPR as a technique for monitoring the purity of high-temperature superconductors is emphasised.