Spin polarons at high temperatures in nonstoichiometricLa$_{1-x}$Mn$_{1-y}$O$_{3}$ manganites

The magnetic properties of the La$_{1-x}$Mn$_{1-y}$O$_{3}$ family of nonstoichiometric lanthanum manganites are studied in the $80<T<640$ K temperature range. The Curie temperature varies nonmonotonically with the growth in the density of Mn$^{4+}$ ions. In the existence range for the paramagnetic phase, magnetic polarons appear in both the orthorhombic and rhombohedral phases. In the range of paramagnetism, the temperature dependence of the magnetic susceptibility is nonlinear and can be fitted by the Curie law with the temperature-dependent Curie constant.