INELASTIC-SCATTERING IN THERMAL TRANSPORT-PROPERTIES OF DEFORMED COPPER SINGLE-CRYSTALS

Measurements have been performed of the thermal conductivity k(T) on copper single crystals as a function of torsional deformation and temperature in the He-3 temperature region. We also carried out measurements of the deformation-thermomagnetic effect on the same samples, because this effect is not only determined by the strain in the sample but also by the Lorenz number (L=kρ/T). In a limited number of experiments, we found indeed an anomalous behavior analogous to the measurements of Fedotov and Mezhov-Deglin. We can distinguish two types of anomalous behavior: a linear temperature dependence of k(T) with a slope smaller than expected on the basis of the Wiedemann-Franz law, and furthermore we observed in some samples a nonlinear temperature dependence of k(T). These observed phenomena in k(T) are ascribed to dynamic electron-dislocation scattering and are confirmed by the deformation-thermomagnetic effect measurements. The data are compared with the recent model of Mukhin for electron-disolocation scattering. This model gives a better qualitative description of the experimental results as does the simple vibrating string model developed by Granato. © 1990 Plenum Publishing Corporation.