The magnetic and transport properties of mixed-valence manganites La0.7−xSmxPb0.3MnO3 (x=0,0.1 and 0.3) are investigated. The x=0 phase is indexed in a rhombohedral structure while the rest exhibit orthorhombic symmetry (Pnma). The increase of x causes a decrease in the spin–coupling interaction between the moments of Mn. Hence, the decrease of ferromagnetic transition temperature from 321 to and the saturation magnetization from 80.36 to can be affected by the substitution of La by Sm.
