Paramagnetic Susceptibility of CoCl₂·6H₂O and its Deuterated Salts

Abstract

The paramagnetic susceptibility of a single crystal of CoCl₂·6H₂O was measured by the usual a-c bridge method. Transition to the antiferromagnetic state was observed at about 3.3°K. The easy axis is along the crystalline c axis. The g values determined in the paramagnetic region, below 20°K are: g_c=g_b=4.9 and g_c⊥=2.9. Some considerations about the anisotropic susceptibilities in the paramagnetic state are given from the standpoint of crystalline field theory. The exchange interaction in this salt is discussed considering the interaction path between the magnetic ions which involves the linkages of chlorine atoms or water molecules. The measurements on the deuterated salts are intended to make clear the effect of the hydrogen bond on the magnetic exchange interaction.