摘要
Scanning tunneling microscopy was used to measure the mean lateral dimensions D of grains at the surface of Ni films with thicknesses ranging from 15 to 200nm.The same films were analyzed by x-ray diffraction to obtain the average linear dimensionsδof coherent scattering regions in the direction normal to the film plane(coherence depths).For thin Ni films condensed on single sapphire substrate at room temperature,these two lengths D andδare equal and increase with film thickness.But for films thicker than 130nm,these two lengths have different constant values and D>δ.This is because the coherent scattering depth is not only limited by the grain sizes but also by various defects in the grains.The difference between the constant values of D andδdisappears for films after annealing for 30min at 423K in the ultra-high vacuum system.
作者
WANG De-liang
U.Geyer
王德亮;U.Geyer(National Laboratory for Superconductivity,Institute of Physics,Chinese Academy of Sciences,Beijing 100080;I.Physikalisches Institut der Universitaet Goettingen,Bunsenstrasse 9,D-37073 Goettingen,Germany)
