A capacitive instrument for the measurement of a large range of magnetostriction at low temperatures and high magnetic fields

Abstract

An instrument has been constructed to measure a large range of magnetostriction between room temperature and 4K in a superconductive split-coil magnet. A combination of high sensitivity and large range is achieved by using a variable-gap capacitor to measure the magnetostriction. Consideration has been given to the best way of relating the magnetostriction to the fundamental magnetoelastic coupling coefficients, and to the information that can be obtained by measurements in various crystal planes. In the light of this, the instrument has been designed to make the measurements in the plane containing the magnetic field. The use of the instrument is illustrated by preliminary results for the first basal plane magnetostriction coefficient for terbium.