ON THE MAGNETIC RAMAN-SCATTERING IN CSCOCL3, CSCOBR3 AND RBCOCL3

An analysis of the magnetic Raman scattering in quasi-one-dimensional antiferromagnets CsCoCl3, CsCoBr3 and RbCoCl3 at the magnetically ordered regime is given. We show that discrepancies between experimental observations and the results of previous theories can be removed excellently by taking into account a next-nearest-neighbour ferromagnetic interaction J' along the c axis. We estimate the value of J'/J congruent-to 0.1 in those substances, where J is the nearest-neighbour antiferromagnetic interaction. Modulations of the magnetic structures for both low- and intermediate-temperature ranges are investigated by calculating the weightings of magnetic chains subject to different staggered fields. We estimate domain sizes in the modulated structures for the first time.