One-Dimensionally Disordered δ(Mn-Al) Structure in Vacuum Co-Deposited Film

Abstract

In vacuum co-deposited film of manganese and aluminium, a disordered layer structure is found in the intermediate stage of heating, at a temperature between 500 and 600°C, when the film has a composition in the range between 25 and 35 at. per cent of manganese. Its reciprocal lattice is investigated by electron diffraction. The structure is interpreted on the basis of δ(Mn-Al) structure. For the combined atomic layer ot 8.5 A thickness parallel to (010) plane, another stacking position denoted by C than the usual one denoted by B in the δ(Mn-Al) structure is found to be possible. This position gives a new stacking order of AC which may be considered as an antipode of the δ(Mn-Al) structure, the usual δ(Mn-Al) structure being denoted by AB-structure. Here the lateral displacements of B- and C-layers relative to A-layer are approximately given by a m /2 and c m /2 respectively, where a m and c m are two translational vector parallel to the layer. The observed extinction rule for the diffraction spots and th...