Crystal structure and magnetic properties of 6H-perovskite Ba3NdRu2O9

Magnetic properties of a quaternary oxide Ba3NdRu2O9 are reported. This com pound adopts the 6H-perovskite structure with space group P6(3)/mmc, in whi ch the cation sites within the face-sharing octahedra are occupied by ruthe nium ions and those within the corner-sharing octahedra are occupied by neo dymium ions. Powder neutron diffraction, powder X-ray diffraction, magnetic susceptibility, magnetization, and specific heat measurements were carried out. It was found that the crystal phase transition and magnetic transitio n occurred at ca. 120 K and 24 K, respectively. The crystal structure below 120 K is monoclinic with space group C2/c. Neutron diffraction data collec ted at 10 K show that Ba3NdRu2O9 has a long-range ferromagnetic ordering of Nd3+ ions. The ordered magnetic moment of Nd3+ ions is 1.65(8) mu (B). The direction of ordered moments is parallel to the c-axis. (C) 2001 Academic Press.