Study on the Ordered Alloys of Gold-Manganese System by Electron Diffraction, II. Au₄Mn

Abstract

The ordered Au₄Mn alloy has been investigated by electron diffraction, using oriented, evaporated films. This ordered alloy has been found below about 400°C to have the body-centred tetragonal unit cell which is 2.5 times as large as the fundamental cell in volume. The structure is isomorphous to that of Ni₄Mo and belongs to the space group I4/m−C_4h⁵. This structure is not the so-called anti-phase domain structure. Some qualitative discussions have been given of the structural transition between the ordered Au₄Mn and Au₃Mn and of the origin of ferromagnetism in Au₄Mn, on the basis of the proposed structure model.