Nm-sized crystallites embedded in single crystalline films of magnesium oxide

Composite films of magnesium oxide embedding metals such as gold, iron and chromium are prepared by the simultaneous deposition technique onto cleavage surfaces of sodium chloride and characterized by high resolution electron microscopy. These metals grow epitaxially and uniformly inside magnesium oxide films as crystallites of a few nm in size. The thickness of the crystallites is estimated to be a few atomic layers. The observation of isolated single atoms or atomic clusters is attempted under an off-Bragg condition. For composite films of iron and magnesium oxide, a heat treatment at 5000C for two hours brings about the growth of γ-iron crystallites. A strain field at the periphery of the γ-iron crystallites is analysed. For composite films of chromium and magnesium oxide, chromium crystallites of around 1 nm in size grow epitaxially inside magnesium oxide film with two kinds of orientation. (orig.)