Optical Mode Scattering Contribution to Electrical Resistivity in Zirconium Hydride

Electrical resistivity measurements on fcc Zr${\mathrm{H}}_{1.54}$ and fct Zr${\mathrm{H}}_{1.96}$ between 1.2°K and 400°K have revealed a sizeable optical mode scattering contribution. Excellent fits to the data are obtained using a simple additive combination of Grüneisen and Howarth-Sondheimer functions for the respective acoustical and optical mode scattering contributions. The corresponding acoustical and optical mode characteristic temperatures are in good accord with values derived from earlier inelastic neutron scattering experiments.