Electron-beam growing and purification of W crystals

High-purity W single crystals have been grown by the electron-beam floating zone melting technique. The structural quality of these crystals was subse quently improved by the application of a strain-annealing technique. X-ray diffraction methods revealed a near-perfect crystallographic structure. Wel l-ordered clean W surfaces free from all contaminants were obtained by a tw o-step heating procedure. Low-energy ion scattering and Auger electron spec troscopy confirmed that the cleaning procedures removed all impurities and that the crystal faces expose only W in the outermost atomic layers. Thin l ayers of Re were deposited on a W(1 1 0) single crystal by magnetron sputte ring and investigated by ion scattering and Auger electron spectroscopy. (C ) 2001 Elsevier Science Ltd. All rights reserved.