Effect of anionic substitution on the structural and magneto-electrical properties of La–Ca–Mn–O perovskite manganites

Abstract The role of anion substitution of oxygen by fluorine in La 0.7 Ca 0.3 MnO 3 − δ F x ( x =0.0 and 0.6) system has been investigated by means of X-ray powder diffraction, electrical resistivity and magnetization measurements. The oxygen content of the samples, estimated by a redox back titration method, decreases with doping while the lattice parameters and unit cell volume increase slightly. The Curie temperature and the metal-insulator transition temperatures of the samples are also found to increase with doping. The deduced magnetoresistance is slightly higher for the doped sample.