Interaction Effects in Potassium Ferricyanide

The character and magnitude of the exchange interaction between the ferric ions in K 3 Fe(CN) 6 have been investigated by, (1) observation of the paramagnetic resonance spectrum of coupled Fe-Fe pairs in semidilute crystals and, (2) adiabatic demagnetization of concentrated crystals. The results show that the exchange between magnetically similar ions contains an appreciable anisotropic part of the order of 0.07 cm -1 . No lines corresponding to dissimilar ion pairs were found. From the two types of experiments, it is concluded that the isotropic part of exchange between similar ions, J s , is about 0.25 cm -1 and that the exchange between dissimilar ions is very small.