Structural, magnetic and magnetotransport properties of La0×7–xCexBa0×3MnO3 (x = 0×0–0×4)

Structural, magnetic and magnetotransport properties of La o-7-xCexBao,3MnO3 (x = 0–04) have been investigated although some unreacted secondary phases of CeO2 were present. The rhombohedral structure (R-3c) for x = 0 transforms to orthorhombic with the space group Imma for x = 0,3. All samples showed ferromagnetic transition above 300 K and a negative magnetoresistance. For x > 0,1, magnetization data measured at 1 T showed a decrease at low temperatures (T < 50 K) due to antiferromagnetic coupling between Ce-local moments and Mn-moments. For x = 0,4, the resistivity showed a maximum around 200 K which corresponds to ordering temperature of cerium. Since these results are similar to that observed in the Sr-containing La 0-5xCexSro-5MnO3 (x =0-0,4) system, we suggest that the cerium ions are in the trivalent state and the anomalous behaviour has been attributed to a Kondo-like effect.