Magnetic structure of CuCrO2: a single crystal neutron diffraction study

This paper presents results of a recent study of multiferroic CuCrO2 by means of single crystal neutron diffraction. This system has two close magnetic phase transitions at T-N = 24.2 K and T-mf = 23.6 K. The low temperature magnetic structure below Tmf is unambiguously determined to be a fully three-dimensional proper screw. Between T-N and T-mf antiferromagnetic order is found that is essentially two-dimensional. In this narrow temperature range, magnetic near neighbor correlations are still long range in the (H, K) plane, whereas nearest neighbors along the L direction are uncorrelated. Thus, the multiferroic state is realized only in the low temperature three-dimensional state and not in the two-dimensional state.