Localisation of Mn 3d states in semi-Heusler compounds

Abstract CoV 1− x Mn x Sb and NiTi 1− x Mn x Sb solid solutions are studied. For x (Mn)⩽0.3, Mn states are localised below E F , the resistivity is metallic, magnetic interactions are weak. Near x =0.35, a semiconducting behaviour appears in both series, and ferromagnetic interactions strongly increase. For x >0.5, a metallic regime is recovered. This is attributed to Anderson localisation of 3d states due to atomic and magnetic disorders.