MAGNETIC-STRUCTURE OF DY2CR2C3

In the carbide Dy2Cr2C3, only the dysprosium atoms are known to carry magnetic moments. Their collinear antiferromagnetic order at 2 K was d etermined from neutron powder diffraction data. The primitive magnetic cell contains four dysprosium atoms and corresponds to the monoclinic C-centered nuclear cell. The magnetic moments are perpendicular to th e monoclinic b axis, with an angle of delta=37.7(+/-2.2)-degrees to th e c axis. The experimentally determined moments of mu(exp) = 8.62(+/- 0.11)mu(B) are smaller than the theoretical values of mu(s) = 10.0mu(B ), which is ascribed to crystal field effects. The Neel temperature of T(N) = 23(+/-1) K is confirmed by the temperature dependence of the m agnetic reflections.