Electrodeless methods for conductivity measurement in metals

Abstract

The bulk of the article is concerned with a critical discussion of inductive, electrodeless techniques that enable the resistivity of a metal to be investigated, especially by the use of massive samples, with or without the presence of a strong magnetic field. The principal methods are the following: modification of the inductance of a coil by a metal core, eddy current decay, `hard' helicons in a rigidly mounted sample, `soft' helicons in an elastically mounted sample and torque on a sphere turning in a steady transverse field. The theory underlying the methods is expounded, but greatest attention is paid to the variety of disturbing effects that can introduce significant errors, and to the refinements of technique and analysis needed to minimize them. Although the literature is reviewed in some detail, much of the material is new.