Hume-Rothery effects in amorphous and quasicrystalline Al–Cu–Fe

A detailed comparison of the amorphous and the quasicrystalline state of Al–Cu–Fe is presented. The samples were prepared amorphously at low temperature. After several annealing steps within the amorphous phase they were transformed into the quasicrystalline state at T=700 K. The atomic structure as well as electronic transport properties for both phases have been investigated. Electron diffraction measurements of amorphous Al–Cu–Fe show the atomic structure as electron induced. The dominant structural peak shifts nearly parallel to 2kF, the diameter of the Fermi-sphere, as a function of composition. At the corresponding composition its position is exactly coinciding with one of the two most dominant peaks of the icosahedral phase, indicating that this phase is Hume-Rothery stabilized as well. The electrical conductivity as well as the Hall coefficient indicate strong similarities between both phases. In the amorphous phase magnetic effects are observed.