Abstract
La0.67-xDyxPb0.33MnO3 (x=0.00 and x=0.10) were elaborated by the solid state method and checked by X-ray diffraction. Close to magnetic temperature transition, the order transition and the critical behavior were investigated by dc magnetization measurements versus x composition. The critical properties were investigated through various techniques such as modified Arrott plot (MAP), Kouvel-Fisher (KF) method and critical isotherm (CI) analysis based on the data of static magnetic measurements recorded around the Curie temperature T-C. The values of critical exponents (beta and gamma) estimated were found to lie between those predicted for a 3D-Ising model for x=0.00 and those of 3D-Heisenberg model for x=0.10. The reliability of the critical exponent's values was confirmed by the Widom scaling relation and the universal scaling hypothesis. The change in the universality class should be due to the increase of the Dy content.