Magnetic structure of CuCrO ₂: A single crystal neutron diffraction study

This paper presents results of a recent study of multiferroic CuCrO ₂by means of single crystal neutron diffraction. This system has two close magnetic phase transitions at T _N=24.2K and T _mf=23.6K. The low temperature magnetic structure below T _mf 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.