Low-temperature internal friction in (Co$_{45}$Fe$_{45}$Zr$_{10}$)$_{x}$(Al$_{2}$ O$_{3}$)$_{100-x}$, Co$_{x}$(CaF$_{2}$)$_{100-x}$, and Co$_{x}$(PZT)$_{100-x}$ nanocomposites

Elastic (G) and inelastic (Q –1) properties of (Co$_{45}$Fe$_{45}$Zr$_{10}$)$_{x}$(Al$_{2}$ O$_{3}$)$_{100-x}$, Co$_{x}$(CaF$_{2}$)$_{100-x}$, and Co$_{x}$(PZT)$_{100-x}$ ($x$ = 23–76 at %) nanocomposites synthesized by ion-beam sputtering have been studied in the temperature interval of 170–270 K. Internal friction maxima have been found in the temperature interval of 225–245 K. It has been established that the amplitude of these maxima, which are associated with atom hopping within metallic grains, increases with the metallic-phase content.