Flow stress of normal and superconducting indium

Measurements of the flow stress of normal and superconducting indium are presented. These are explained by a model which involves only the difference in thermal activation of the mobile dislocations in the two states and yields a flow stress difference which, for pure materials, can be expressed in terms of the thermal conductivity as (σ N − σ S ) ~ ln (K N /K S ). This relation is compared with experiment for pure indium and lead. The flow stress is also shown to provide a sensitive method of observing flux trapping in pure superconductors.