MAGNETIC-PROPERTIES OF BA2(UCU)O6

Bulk magnetic and neutron diffraction studies have been carried out to determine the magnetic properties of Ba2 (UCu)O6 at low temperatures. In the frame of pseudo-perovskite unit cell, the magnetic ordering of the Cu moments at 1.5 K can be described by the propagation vector k = {0, 0, 0}, corresponding to the G(+ - + -) or equivalent A{+ - - +} configuration with the moment alignment close to the [110] direction. As concluded from both neutron diffraction and susceptibility data, Ba 2(UCu)O6 exhibits quasi-two-dimensional antiferromagnetic properties, resulting from a weak interaction between antiferromagnetically couple d Cu layers. The magnetic moment of Cu2+ ion amounts to (0.86 +/- 0.23 )mum(B) at 1.5 K.