ORDERING OF DZYALOSHINSKII-MORIYA VECTORS AND UNIDIRECTIONAL ANISOTROPY IN SPIN-GLASSES

The mean-field theory of the Dzyaloshinskii-Moriya (DM) interaction in spin glasses is developed. Due to the fact that a microscopic DM vect or is defined up to a sign there exist additional internal degrees of freedom caused by ordering of microscopic DM vectors below the freezin g temperature. This is a reason of an appearance of the macroscopical unidirectional anisotropy. The value of the unidirectional anisotropy field is proportional to the value of the external cooling field H for weak H and runs to saturation at strong H.