La_0.7 Ca_0.3 Mn_0.95 M_0.05 O₃ manganites (M = Al, Ga, Fe, Mn, and In): Local structure and electron configuration effect on Curie temperature and magnetization

X-ray diffraction and magnetization measurements have been carried out in La_0.7 Ca_0.3 Mn_0.95 M_0.05 O₃ manganites (M = Al, Ga, Fe, Mn, and In). It was found that the samples belong to orthorhombic phase and lattice parameters increase with increasing ionic radius of the dopants. Curie temperature, T_C, changes with doping due to a difference between the electron configuration (E-factor) and ionic radius (S-factor) of the dopants and manganese trivalent ion. The E-factor affects the T_C stronger than the S-factor and causes the T_C decrease. The S-factor can cause both positive and negative change in Δ T_C. The Δ T_C change, caused by the S-factor, is positive if ionic radius of the dopant is less than that of Mn^{3 +} ion, and negative in opposite case, if dopant ionic radius is larger than that of Mn^{3 +} ion. Saturation magnetization of the manganites decreases continuously with increasing ionic radius of the substituents and almost independent of magnetic nature of the dopants.