Structures and Properties of Oxide Superconductors

Abstract

Using chapter "▶ Electrovalent Crystal Structures and Chemistry," and especially the crystal chemistry of metal oxides as a platform, this chapter will examine basic structures and properties of oxide superconductors, particularly the so-called high-temperature (HT) superconductors. The two conditions for true superconductors, zero resistance (or resistivity), and a demonstrated Meissner effect (levitation of a magnet) are described, the latter as the exclusion of magnetic flux in the superconducting state. However, this chapter begins with a brief overview of more conventional metal or alloy superconductors in order to establish a relationship between these more conventional superconductors in contrast to oxide superconductors. It is pointed out that since the popular theory of superconductivity, the BCS theory, does not elucidate specific mechanisms which provide any predictability or avenues for guided exploration, future innovations may hinge on novel design strategies to improve existing systems.