Publisher's Synopsis
The aim of this special issue is to collect in one place a series of artic les devoted to the variety of phase transitions and complex ordering pheno mena which take place prior to the onset of superconductivity. Most of th e literature to date on these transitions, especially those falling betwe en room temperature and the onset of superconductivity, has been inter preted in terms of magnetic or purely electronic mechanisms. By contr ast, this special issue draws on studies such as those using diele ctric, ultrasonic and microwave methods which give information on the under lying electric rather then magnetic or purely electronic properties of th e phase transitions. Such dielectric, electrical ferrodistortive prope rties are less familiar to scientists working with conventional;metal lic superconductors since in that case they play a relatively minor role. For those scientists who have devoted years of effort to the study of ferro distortive phase transitions in perovskite oxides, including those which involve semiconductor properties (e.g. positive temperature;coeff icient (PTC) effect), the dielectric and electrical properties are well known to play a key role in the mechanism of the transition. This issue , by bringing to the high temperature superconductivity field a somew hat different perspective, aims to help widen our scientific under standing of this new class of superconductors.
