Metallic Conduction at High Frequencies and Low Temperatures

Abstract

Publisher Summary This chapter discusses concepts related to metallic conduction at high frequencies and low temperatures. Much of the stimulus for this subject has come from the discovery by H. London that at high frequencies a superconductor is no longer without resistance, and much effort has been devoted to obtain measurements of this resistance in the hope of gaining greater understanding of the nature of the superconducting state. But London's work also showed that in normal (that is nonsuperconducting) metals at low temperatures, there are effects arising from the long free paths of the conduction electrons that make normal metals a profitable field of study. The function of the low temperature is to increase the electrical conductivity to such a value that the electronic free path is comparable with the depth of penetration (skin depth) of the high-frequency field. In this chapter, experimental methods for the measurement of resistance and the measurement of reactance are described. Anomalous skin effect and microwave behavior of superconductors are also discussed in the chapter.