Decagonal quasicrystals, which have a long-range order but do not have translational symmetry, are an exciting object of research in modern solid-state physics. Unlike periodic crystals, whose structure repeats itself in space, quasicrystals exhibit an aperiodic order based on mathematical rules such as the golden ratio.
The discovery of stable decagonal quasicrystals in the Al-Fe-Cr and Al-Fe-Mn alloy systems is an important step in understanding the formation and properties of these unique materials. The stability of decagonal phases makes it possible to conduct systematic studies of their structure, electronic structure, and physical properties at various temperatures and compositions.
Metallographic studies have shown that decagonal quasicrystals in these alloys are usually formed by peritectic reactions from the melt. The microstructure of the alloys consists of decagonal grains surrounded by other crystalline phases. X-ray and electron diffraction techniques have confirmed the decagonal symmetry and quasi-periodic order of these phases.
In the Al-Fe-Cr system, the decagonal phase was formed only after prolonged thermal annealing at temperatures below solidus (maximum 1090 °C). A strong temperature dependenceof the region of existence of the decagonal phase was observed in the Al-Fe-Mn system.
The electronic properties of decagonal Al-Fe-Cr and Al-Fe-Mn quasicrystals are studied using resistivity measurements, Hall effect measurements, and photoelectron spectroscopy. The results obtained indicate the presence of a pseudogap near the Fermi level, which indicates strong electron scattering and specific electron correlations.
The study of stable decagonal quasicrystals in the Al-Fe-Cr and Al-Fe-Mn systems contributes to the expansion of fundamental knowledge about quasicrystalline materials and opens up prospects for the development of new alloys with unique properties.
Author: D. Pavlyuchkov, S. Balanetskyy, W. Kowalski, M. Surowiec, B. Grushko
The Institute: Institut für Festkörperforschung, Forschungszentrum Jülich, D-52425 Jülich, Germany, I.N. Frantsevich Institute for Problems of Materials Science, 03680 Kiev 142, Ukraine, Institute of Materials Science, University of Silesia, 40007 Katowice, Poland