Structural Aspects of the Crystallographic-Magnetic Transition in LaVO3 around 140 K

摘要: The perovskite-like compound LaVO[sub 3] undergoes a crystallographic-antiferromagnetic transition at about 140 K. structure of has been determined room temperature and just above (150 K) below (100 the transition. Synchrotron X-ray neutron powder diffraction techniques were used. lattice parameter variation vs structural refinements revealed that is GdFeO[sub type; namely, it orthorhombic with parameters [alpha] = 5.55548, b 7.84868, c 5.55349 [angstrom] space group Pnma. distortion very similar to isostructural LaFeO[sub 3]. At 100 K, transformation temperature, monoclinic parameters: 5.59360, 7.75951, 5.56490 [angstrom], [gamma] - 90.125[degrees] P2[sub 1]/a. In all V sites are equivalent, but two independent sites, V1 V2, observed in structure. These form alternate layers along axis. Above transition, octahedra tilted around three crystallographic axes elongated [110] direction. elongation increases transitionmore » occurs different directions 90[degrees] apart, V2 octahedra.« less