Transport properties of Ti-Zr-Ni quasicrystalline and glassy alloys

Abstract

We report on measurements of the temperature dependence of the electrical resistivity (ρ), thermopower (S), and thermal conductivity (κ) of Ti-Zr-Ni alloys between 10 and 300 K. A series of Ti-Zr-Ni quasicrystals (QCs) Ti40Zr40Ni20, Ti45Zr35Ni20, and Ti50Zr30Ni20 and metallic glasses Ti35Zr45Ni20 and Ti40Zr40Ni20 was prepared to systematically study the compositional and structural dependences of their transport properties. The resistivity of all these alloys was found to be very weakly temperature dependent with a negative temperature coefficient of resistance. Further, the observed increase in electrical resistivity with increasing Ti/Zr ratio is most likely due to the increase in disorder. The S/T against temperature curves exhibited a maximum between 20 and 50 K and a noticeable deviation from the expected linear behavior in S(T) at higher temperatures. Such observations in the thermopower of QCs have been attributed to the electron-phonon enhancement and phonon drag effect. The measured thermal conductivities were analyzed by separating the electronic and phonon contributions that provide a reasonable explanation for plateau-type feature in κ(T) of QCs. Our present results suggest that the transport properties of glassy phase are influenced by the same mechanisms as those of quasicrystalline phase.