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MM: Fachverband Metall- und Materialphysik
MM 11: Liquid and Amorphous Metals III
MM 11.3: Talk
Monday, March 14, 2011, 16:15–16:30, IFW D
On physical properties and atomic structure of Al-Pd alloys — •Nan Jiang and Peter Häussler — Chemnitz University of Technology, Institute of Physics, 09107 Chemnitz, Germany
In recent years we reported on an electronic influence on phase stability of all the Al-3d-TM alloys (TM: Sc, ..., Cu). The electronic influence is based on an internal exchange of momentum between global subsystems, namely the electronic system and the forming static structure. Both systems come into resonance to each other. The resonance is enhanced by a hybridization effect between the Al-p- and the empty TM-d-states causing a reduced effective electron density of the total system. Structure formation, phase stability and the evolution of electronic transport properties were found to be strongly related. In the present contribution we start to replace the 3d-TM elements by the 4d-TM.
For thin films of amorphous AlPd alloys, deposited at a temperature around 4 K, the resistivity and the thermopower have been measured from 4 K to 345 K, the atomic structure after annealing to room-temperature by TEM. The thermal stability is largest around 30-40 at%Pd and hence supports our assumption of hybridization of Al-3p electrons with the Pd-4d-states. Comparing the position Kpe of the first peak in S(K), the structure factor, with 2kF, the diameter of the Fermi sphere, we extract another composition around 60 at%Pd, where again there is an electronic stabilizing effect, but now without hybridization.