Surface diffusion of dysprosium on the W(1 1 1) facet

• Published in: Applied surface science Vol. 230; no. 1; pp. 81 - 87
• Main Authors: Biernat, T., Błaszczyszyn, R.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 31.05.2004; Elsevier Science
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Dysprosium; Exact sciences and technology; Field emission current fluctuations method; Physics; Surface diffusion; Tungsten; 68.90.+g; Field emission current fluctuations method; Tungsten; Surface diffusion; Dysprosium; 05.40.+j; 79.70.+q; Temperature dependence; Work functions; Field emission; Current fluctuations; Spectral functions; Coverage rate; Spectral analysis; 05.40.+j Field emission current fluctuations method; Adsorbed layers; Rare earths; Transition elements; Diffusion coefficient; Spectral density; Diffusion; Activation energy; Facet; Strength functions
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2004.02.054

Diffusion of dysprosium on the (1 1 1) facet of a tungsten micromonocrystal was investigated by means of spectral analysis of field emission current fluctuations. The experimental spectral density functions of the current fluctuations were analysed by using Gesley and Swanson’s theoretical spectral density function, which enables to determine the surface diffusion coefficient D for dysprosium. Derived from the temperature dependence of D, the diffusion activation energy E is presented for some Dy coverages θ (1 1 1) . In the temperature range 400–600 K, the E first drops from 1.25 eV per atom at θ (1 1 1) ≈0.25 ML to 0.48 eV per atom at θ (1 1 1) ≈1 ML (corresponding to the minimum of the work function of the system), then increases to 1.03 eV per atom at θ (1 1 1) ≈1.3 ML. The results are discussed from the aspects of the substrate structure and interaction in the adsorbed layer.