Growth and electrical and optical properties of Al(Pd,Mn) alloy thin films produced by simultaneous vapor deposition of the components

Abstract

Thin films of binary and ternary alloys in the system Al–Pd–Mn were deposited by simultaneous evaporation of the metals from separate sources on carbon substrates (a-C, HOPG), or on glass plates at temperatures up to 500 °C. Film structure and composition were characterized by TEM, electron diffraction, and EDX. In the binary system Al–Mn, the homogeneous icosahedral phase nucleated for Mn concentrations around 14 at.%, at rather low deposition rates. Crystalline phases precipitated at lower and higher Mn contents, as well as at higher deposition rates and/or higher substrate temperatures. Only crystalline phases were identified in Al–Pd deposits. For the ternary system Al–Pd–Mn, icosahedral order was observed for Al contents above 75 at.%, while crystalline Al–Pd phases segregated at lower Al contents. For films with icosahedral order, the electrical resistance revealed negative temperature coefficients down to 10 K. Optical reflectivity and absorption showed only little variation from the visible to the near IR.