Distribution cationique et distorsion cristalline dans les manganites spinelles NiCrxMn2−xO4

The atomic distribution in the spinels NiCrxMn2−xO4 has been studied by X ray scattering. All these compounds, except NiCr2O4, have a cubic structure, after quenching from temperature preparation (800°C) to 25°C. Lattice distortion only occurs for Cr-rich compounds and for temperatures lower than 25°C. The irregular parameter variation with the composition may be interpreted by the absence of manganese in the B sites, for the range 1.5 ⩽ x ⩽ 2.