Structure characterization and magnetic properties of Ln0.7Pb0.3MnO3 (Ln=La, Nd, and Pr) manganites

Ln 0.7Pb0.3MnO3 (Ln=La, Nd, Pr) oxides have been synthesized by using the conventional ceramic method. The magnetic measurements show that Tc values alter considerably by substituting different rare earth ions. The zero field cooled (ZFC) magnetization curve of La manganite shows almost the same magnitude with the field cooled (FC); however, the curve of Nd manganite drops to zero at low temperatures. The magnetization is hardly saturated by the external field for Pr and Nd manganites due to the spin-glass nature. These facts are in good agreement with the lower ionic radii of the Nd ions and the corresponding large distortion of their perovskite structures.