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 E -type antiferromagnetic order below T N ∼ 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 3.4 μ B .