Titanium metastable phases in sputtered Ti-Fe films and their influence in the electrical resistivity -: art. no. 144417

The granular microstructure of sputtered Ti-Fe films and their electrical transport properties have been investigated correlating a wide x-rays diffraction characterization with dc resistivity measurements from 7 to 300 K. The experimental results show that the argon pressure and the rf sputtering power can efficiently regulate the formation of the different titanium metastable phases at room temperature. These bcc and modified hcp titanium phases result from an effective quenching of the sputtered particles, mainly favored with the sputtering gas atmosphere. For Ti-Fe alloys with low Fe content (around 5%), the resistivity measurements display a minimum centered about 47 K which fades away on increasing the sputtering power. Both the low-temperature anomaly and its evolution with rf power are explained on the basis of the transition from hcp Ti to bcc Ti grains and the huge difference between their iron solubilities. Unlike the hcp Ti grains, the high content of iron in the bcc Ti grains (similar to22 at. %) eliminates the magnetic Kondo scattering responsible for the observed minimum in the resistivity.