The Crystal Structure of Lanthanum-Strontium Manganites

The lanthanum manganite-strontium manganite system has been examined as a function of the lanthanum content. The perovskite phase is stable from 23% to 100% lanthanum. At the lower limit of stability it is of cubic symmetry the unit cell becoming rhombohedral between 50% and 60% lanthanum. In the lanthanum manganese oxygen system of general formula LaMno x the value of x has been varied between 3 24 and 3 07. Over the entire range the structure is of the perovskite type with small type of cell. At the oxygen rich end of the system the symmetry is rhombohedral while at the other end it is cubic. In both systems the relations between the lattice parameters and composition and magnetic Curie temperatures are indicated.