Stress-induced compositional modulations in ultrathin Au–Ni solid solutions grown on Au(001) by molecular beam epitaxy: a temperature X-ray diffraction study

• Published in: Thin solid films Vol. 318; no. 1; pp. 204 - 208
• Main Authors: Abadias, G, Schuster, I, Gilles, B, Marty, A
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 15.04.1998; Elsevier Science
• Subjects: Applied sciences; Au–Ni solid solution; Composition and phase identification; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Metals. Metallurgy; Molecular beam epitaxy; Physics; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thermal annealing; Thin film structure and morphology; Ultrathin alloy; Au–Ni solid solution; Molecular beam epitaxy; Thermal annealing; Ultrathin alloy; Stresses; Ultrathin films; Epitaxial layers; Nickel alloys; Gold base alloys; Modulated materials; Experimental study; Binary alloys; Graded junction; Solid solutions; Mismatch lattice; Chemical composition; Transition element alloys
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/S0040-6090(97)01166-8

Ultrathin Au 1− c Ni c alloys have been grown at room temperature by molecular beam epitaxy on Au(001) buffer layers. The Ni concentration c, ranging from 0.2 to 0.4, is much higher than the bulk solubility. The structural evolution with temperature has been investigated by X-ray diffraction measurements. The AuNi layer is coherently strained on the Au buffer and a modulated structure develops along the growth direction upon annealing at 220°C. The period of the modulation is around 6–8 Å and gives rise to satellite peaks. A simulation has shown that these peaks may be reproduced by a superlattice cell in which monoatomic Ni planes are separated by three or four Au atomic planes. At higher temperatures, there is a diffusion of Ni in the surrounding Au regions, leading to a homogeneous and dilute AuNi solid solution.