Resonance paramagnetique electronique du manganese divalent dans l'alumine β

Single crystals of β alumina doped with manganese ions have been prepared by high frequency induction melting and slow cooling, followed by Na⁺ - Mn²⁺ exchange in molten MnCl₂. EPR study shows that Mn²⁺ ions occupy two kinds of sites. The first one, with an axial zero field tensor corresponds to the tetrahedral positions in the spinel blocks, close to the sodium planes. This seem to indicate that aluminium vacancies in β alumina are partly located in this site. The other, with an orthorhombic zero field tensor, and high D and E values, belongs to the conduction planes.