ELECTRICAL-TRANSPORT PROPERTIES OF CU3GE THIN-FILMS

Resistivity, Hall-effect, and magnetoresistance measurements have been performed in the temperature range 4.2-300 K on thin films of the epsilon(1)-Cu3Ge phase that has a long-range ordered monoclinic crystal structure. The results show that epsilon 1-Cu3Ge is a metal with a room-temperature resistivity of similar to 6 mu Omega cm. The temperature dependence of resistivity follows the Block-Gruneisen model with a Debye temperature of 240+/-25 K. The density of charge carriers, which are predominantly holes, is similar to 8X10(22)/cm(3) and is independent of temperature and film thickness. The Hall mobility at 4.2 K is similar to 132 cm(2)/V s. The elastic mean free path is found to be similar to 1200 Angstrom A, which is surprisingly large for a metallic compound film. The results show that the residual resistivity is dominated by surface scattering rather than grain-boundary scattering. An increase in Ge concentration above 25 at. % (but less than 35 at. %) is found to affect the resistivity and Hall mobility, but not the density of charge carriers.