Comparison of the temperature dependence of the mechanical dissipation in thin films of Ta ₂ O ₅ and Ta ₂ O ₅ doped with TiO ₂

Here we report the first results comparing the temperature dependence of the mechanical dissipation in thin films of Ta_2O_5 and Ta_2O_5 doped with TiO_2, of a type suitable for use in the multilayer optical coatings for advanced gravitational wave detectors. The results indicate that doping Ta_2O_5 with TiO_2 can significantly alter the distribution of activation energies associated with the low-temperature dissipation peak.