Neutron powder diffraction study of crystal and magnetic structures of orthorhombic LuMnO3

The crystal and magnetic structures of orthorhombic, perovskite-type LuMnO3 are described on the basis of neutron powder diffraction data; space group Pbnm, a=5.19865(14)Å, b=5.78853(15)Å, and c=7.2970(2)Å at 298 K. There is a strong cooperative Jahn–Teller (JT) distortion of the MnO6-octahedra resulting in orbital ordering and EE-type antiferromagnetic order below TN∼40TN∼40 K. The magnetic propagation wave vector is commensurate k=b∗/2 at 8 K and no indications of any magnetic phase transitions are seen in susceptibility data. The ordered magnetic moment for Mn is 3.4μB.