Thermal Expansion Measurements Using the Strain Gauge Technique with Kelvin Double Bridge

Abstract

The strain gauge technique is known to be very useful for thermal expansion measurements under pressure. However, there is a problem to be resolved in this method; Wheatstone bridge that is conventionally employed in this technique is subject to a spurious effect resulting from lead-wire resistances. Here we report that such the effect is remarkably suppressed by using Kelvin double bridge instead of Wheatstone bridge. As an example of this application to heavy fermions, we present results of thermal expansion measurements of UGe 2 and ZrZn 2 that have been attracting much attention in the field of strongly correlated electron physics.