Phase formation induced by ion irradiation and electrical resistivity of aluminum–3d-transition-metal alloys

The phase formation, in particular amorphization, caused by 500-keV Xe⁺ ion irradiation of thin multilayered films of Al-Ti, Al-V, Al-Cr, Al-Mn, Al-Fe, Al-Co, and Al-Ni has been investigated. At a substrate temperature of 100 K during the irradiation, all these alloy systems are found to become amorphous for aluminum-rich compositions. At room temperature, the formation of structurally simple-crystalline solid solutions over extended compositional ranges, as compared to thermodynamic equilibrium, is observed. The electrical resistivity of amorphous Al₈₃{M}₁₇$ alloys, where M=Ti, V, Cr, Mn, Fe, Co, or Ni, is found to vary systematically as a function of transition-metal element. A maximum is observed around Fe, for which the d-electron states coincide with the Fermi level. This behavior suggests that scattering of the conduction electrons by the 3d-electron states plays a dominant role. A comparison with x-ray photoelectron spectroscopy data from the literature suggests that the resistivity of amorphous Al₈₃{M}₁₇$ alloys can be directly correlated to the position and width of the d-electron states.