DC Transport Critical Currents

Abstract

This part introduction presents an overview of the key concepts discussed in the subsequent chapters. The part introduces the issue of Direct current transport critical currents. It provides a working definition of the concept ‘transport critical current’, introduces the underlying current–voltage behaviour of superconducting materials and makes a classification of the different dissipation mechanisms which lie at the basis of this behaviour. The part explains the emphasis on the experimental methods used to determine the transport critical current. It discusses the strategy underlying such measurements and shows how they can be compared to the many other experiments used to investigate superconducting materials. The part introduces the nuts and bolts of critical current measurements, discussing the necessary instruments and the experimental details. It argues that because of experimental similarities with critical current measurements, also resistive measurements of the superconducting transition.