Antiferromagnetism in MUO3 (M = Na, K, Rb) studied by neutron diffraction

摘要

Simultaneous refinements of X-ray and neutron powder diffraction patterns taken on the MUO3 perovskite compounds with M = Na, K and Rb, were performed to reveal anisotropy in the temperature factors, mainly of oxygen. No anisotropic thermal motion was found.The magnetic ordering of the compounds has been investigated with low temperature neutron diffraction. It is found that all these compounds show G-type anti ferromagnetic ordering with a similar, orthorhombic magnetic unit cell. The propagation vector could only be determined for the orthorombic NaUO3 Compound and was found to point in the z-direction. The refined magnetic moment for U5+ in these structures was found to be around 0.20(3) mu(B). (C) 2004 Elsevier Inc. All rights reserved.