Effect of Cr doping in La0.7Sr0.3Mn1-xCrxO3 with 0 <= x <= 0.5

The study of perovskite manganites La0.7Sr0.3Mn1-xCrxO3 has been carried ou t. The structure, magnetic and electrical propertius of La0.7Sr0.3Mn1-xCrxO 3 manganites are strongly dependent on the doping level x. The little diffe rence between the ionic radii of Cr3+ and Mn3+ causes no change in the stru cture, the structure remains rhombohedral. A considerable change occurs in magnetic and transport properties with respect to the sample without Cr. Al l the samples present a single magnetic transition from ferromagnetic to pa ramagnetic phase with the decrease of the Curie temperature T-C when x incr eases (x less than or equal to 0.5). The introduction of a different metal, Cr, in Mn-O layer causes a decrease in the value of T-C. The Cr-doped mang anites exhibit a large variation in resistivity values. The resistivity inc reases when the level of Cr increases, and we observe that the temperature TM-SC, indicating the metal-semiconductor transition, decreases.