© 2003 American Institute of Physics

Published in Journal of Applied Physics, Vol. 93 No. 10 (2003) at doi: 10.1063/1.1544482


Polycrystalline La0.96−xNdxK0.04MnO3 has been studied by means of x-ray powder diffraction, dc magnetization, and electrical resistance measurement. La0.96−xNdxK0.04MnO3 initially crystallizes in a rhombohedral distorted perovskite structure. However, an orthorhombic structure is obtained with increasing Nd content more than 20%. Both the rhombohedral and the orthorhombic phases show ferromagnetic order. However, the compound shows a magnetic inhomogeneity behavior with increasing Nd content. With increasing Nd doping, the ferromagnetic order is significantly weakened, and the second magnetic transition occurs at a low temperature and its peak intensity enhances. The resistivity of these compounds also exhibits an imhomogeneity behavior. The rhombohedral phase shows a metal–insulator (MI) transition but the MI transition peak intensity is obviously weakened and broadens with increasing Nd content and a low temperature insulator state is observed in the orthorhombic phase. It is interesting that the second magnetoresistance ratio peak appears at low temperature. It might be due to Nd induced low temperature phase separation between the ferromagnetic metallic and antiferromagnetic insulating state.