Improved Magnetoresistance in Sm0.7-xCexSr0.3MnO3 Manganites Prepared by a Sol–Gel Route

In this work, manganite ceramics of Sm0.7-xCexSr0.3MnO3 (0 ≤ x ≤ 0.3) are prepared by a citrate sol–gel chemical route and characterized. The structure of the obtained samples is refined in the orthorhombic system with the Pnma space group. The doping causes a change in the lattice parameters leading to a decrease in the cell volume. It also increases slightly the grain size of the crystallites. The temperature dependence of resistivity reveals a metal–insulator transition for all samples. The doping shifts the temperature of this transition towards high values. The extracted magnetoresistance for a 5 T magnetic field is enhanced by doping. The highest obtained value increases from 66.70% for x = 0 to 97.96% for x = 0.3.