Mössbauer Evidence for Ferromagnetic Ordering in Copper-IronCyanometallates

A novel member of the Prussian blue family, Cu^II₃ Fe^III (CN)₆₂.3NH₃.6H₂O, was synthesized, in which NH₃ ligands are in stochastic distribution. X-ray diffraction data, zero-field-cooled magnetization and field-cooled magnetization curves, Mössbauer spectra with/without an external field of 5 T and a structural model are presented. This Prussian blue analog displays considerable magnetic hardness below the magnetic transition temperature T_c, which is about 19.8 K. The coercive field determined from the magnetization hysteresis loop at 5 K was 2.76 kOe. The copper-iron cyanometallates have potential applications in the design of novel magnetic systems.