Influence of quantum fluctuations on the ground state of quasi-one-dimensional triangular antiferromagnet CsMnI3

Mn-55 NMR in the quasi-1D triangular antiferromagnet CsMnI3 was investigate d. Six NMR modes corresponding to six spin orientations of Mn ions in eleme ntary magnetic cell were observed. The difference between average values of the Mn spins (S) in magnetically nonequivalent antiferromagnetic chains wa s found. We have determined a new magnetic phase of CsMnI3 in a magnetic fi eld parallel to the hexagonal axis in the range 39-52 kOe. Calculations ind icate that the new phase is a result of the difference between the (S) valu es in neighbouring antiferromagnetic chains. (C) 2000 Elsevier Science B.V. All rights reserved.