The limiting value of<i>x</i>in the ferromagnetic compositions La_{1 x}MnO₃

Abstract

Studies on a large number of compositions among the ferromagnetic self-doped manganites, La1−xMnO3, show that the ferromagnetic Curie temperature increases with x and reaches a maximum value for x = 1/7. Tc remains independent of x for x ≥ 1/7 and the maximum value of the magnetization is obtained for x = 1/8. The presence of a second phase, due to Mn3O4, whose contribution increases with x, is observed in the powder x-ray diffraction patterns for x > 1/8 and the lattice parameters remain independent of x for x > 1/8. The results indicate that the limiting value of x or the extent of self-doping possible in La1−xMnO3 is x = 1/8.