Single crystal magnetization and susceptibility studies on CuCl2⋅DMSO, a salt with quasi 1-d ferromagnetic interactions

Abstract

CuCl2⋅DMSO is one of a series of linear chain spin 1/2 compounds recently shown to have predominantly ferromagnetic interactions in the paramagnetic state. Initial studies1 conducted on powders showed the exchange interaction J to be relatively large (J/k = 45 K) with rather large interchain interactions (J′/J = −0.04). The present paper reports the first single crystal susceptibility and magnetization studies on this compound. The monoclinic compound has been found to order antiferromagnetically at 4.80 K with the easy axis the a axis. The two χ⊥′s are nearly equal, indicating uniaxial anisotropy. A spin-flop transition has been observed when an external field was applied along the easy axis. The magnetic field phase diagram for this transition has been measured down to 2 K in fields up to 9.5 kOe. Using a molecular field model, effective fields have been estimated for the antiferromagnetic coupling between chains and for the spin anisotropy. The antiferromagnetic exchange field is 23 kOe, 3.6% of the effective ferromagnetic exchange field within the chains (Hfm). The anisotropy field was found to be only 6×10−4Hfm, indicating nearly perfectly Heisenberg-type intrachain exchange.