Author: M. A. Evsyukova, G. Yalovega, A. Balerna, A. P. Menushenkov, J. V. Rakshun, A. A. Teplov, M. N. Mikheeva, A. V. Soldatov
Institute: Southern Federal University, 5 Sorge St., Rostov-on-Don, 344090, Russia
LNF, INFN, Italy
National Research Nuclear University MEPhI, Moscow, Russia
Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia
Russian Research Center “Kurchatov Institute”, 123182 Moscow, Russia
The crystal-quasicrystal transition in the Al-Cu-Fe system is a complex and multi-level process that is initiated by changes in the local atomic structure. In this system, where three main elements interact, the formation of the quasi-crystalline phase is due to the stability of specific atomic configurations that minimize the free energy of the system. The first stage is the formation of primary crystals, which are then subject to significant redistribution upon reaching a critical temperature.
Quasicrystals (quasiperiodic crystals) are of considerable interest due to their exceptional properties, which are not inherent in conventional crystalline and amorphous materials. The studies focused on the changes in the local structure around the Al, Cu and Fe atoms during the transition from the quasicrystalline to the crystalline phase. The analysis of the local atomic structure of the quasicrystalline compound Al65Cu22Fe13 and its crystalline analogue was performed using X-ray absorption near-edge spectroscopy (XANES). This made it possible to establish the three-dimensional local atomic structure of the samples. Theoretical analysis was carried out using the self-consistent multiple scattering method in real space (code FEFF8.4) and the finite difference method (code FDMNES2009).
Quasicrystals represent a new class of solids that cannot be characterized in terms of classical crystallography, occupying an intermediate position between amorphous and crystalline materials, while maintaining the long-range order of atoms.
The next step is the formation of interphase boundaries, where atomic groups begin to rearrange themselves, creating more complex ordered structures with pentagonal symmetry. These structural changes are accompanied by distortions in the network and the formation of defects, which significantly complicates the analysis. Studying the local atomic structure using modern methods such as high-resolution electron microscopy and X-ray diffraction allows us to more clearly trace the transition process and identify the key mechanisms that control this transformation.