Crystal and magnetic structure and cation distribution of Mn2-x V1+x O4 spinels ( x = 0 , 1/3 and 1)

J.M. DE PAOLI

MATERIALS RESEARCH BULLETIN

Elsevier Ltd.

Lugar: Amsterdam; Año: 2009 vol. 44 p. 1586 - 1586

0025-5408

e synthesized the spinel-type compounds belonging to the Mn2-xV1+xO4 series with x= 0, 1/3 and 1 as polycrystalline powders. Crystal and magnetic structures we re refined using synchrotron X-ray and neutron powder diffraction. At 300 K all members crystallize in the cubic system, space group Fd3¯m , and show a structural transit ion at low temperature, changing to a tetragonal symmetry (space group I41/amd ). Cations distributions between octahedral and tetrahedral sites we re refined from neutrons diffraction (ND) data and explained based on crysta field stabilization energies (CFSE) and ionic radii. The magnetic unit cell is the same as the crystallographic one, having identical symmetry relations. The magnetic structure was refined as an arrangement of collinear spins, antiferromagnetically ordered, parallel to the c-axis of the unit cell. The refined site magnetic moments are smaller than those obtained from hysteresis cycles of the M vs. H measurements, indicating that some non-c