In situ studies of magnetron sputtered Al–Cu–Fe–Cr quasicrystalline thin films

In situ studies have been performed on thin films in the Al rich region of the Al–Cu–Fe–Cr quasicrystalline phase field. Thin films were grown by magnetron sputtering on atomically flat MgO (0 0 1) and Al O (0 0 0 1) and subsequently studied by 2 3 transmission electron microscopy and X-ray photoelectron spectroscopy. High resolution electron microscopy shows that thin films (-30 nm) grown at room temperature are essentially amorphous. At higher temperatures ()573 K), the film growth is identified to be island mode. Upon subsequent ultra high vacuum annealing at 583 K, the films transform into a mixture of quasicrystalline and crystalline grains. Further annealing results in grain growth. A hexagonal crystalline phase in the films with as2.23 nm and cs1.25 nm was identified as an approximant of the decagonal phase. For annealing temperatures above 848 K, the films phase separate into thick quasicrystalline and thin crystalline regions. 2002 Elsevier Science B.V. All rights reserved.