Crystal Structure and Magnetic Properties of 6H-Perovskite Ba_3NdRu_2O_9

摘要

Magnetic properties of a quaternary oxide Ba_3NdRu_2O_9 are reported. This compound adopts the 6H-perovskite structure with space group P6_3/mmc, in which the cation sites within the face-sharing octahedra are occupied by ruthenium ions and those within the corner-sharing octahedra are occupied by neodymium ions and those within the corner-sharing octahedra are occupied by neodymium ions. Powder neutron diffraction, powder X-ray diffraction, magnetic susceptibility, magnetization, and specific heat meausrements were carried out. It was found the crystal phase transition and magnetic transition occurred at ca. 120 K and 24K, respectively. The crystal structure below 120K is monoclinic with space group C2/c. Neutron diffraction data collected at 10K show that Ba_3NdRu_2O_9 has a long-range ferromagnetic ordering of Nd~(3+) ions. The ordered magnetic moment of Nd~(3+) ions is 1.65(8) #mu#_B. The direction of ordered moments is parallel to the c-axis.