Ferromagnetic order and spin-glass behavior in multi-metallic compound Ni1.125Co0.375[Fe(CN)6] · 6.8H2O

Multi-metallic Prussian blue compound Ni1.125Co0.375[Fe(CN)6] · 6.8H2O has been synthesized. The Mössbauer spectroscopy at room temperature and IR spectra study revealed that the metal ions are bonded through cyanide ligand and the presence of low spin FeIII(S = 1/2) and high spin FeIII(S = 5/2) ions, as showed in these structure: FeIII(S = 1/2)-CN-(CoII/NiII)(96%) and FeIII(S = 5/2)-NC-(CoII/NiII) (4%). The Curie constant of C = 3.00 cm3 K mol−1 and Weiss paramagnetic Curie temperature of θ = 16.43 K were observed in fitting according to Curie–Weiss law. These results indicate that there existed a ferromagnetic exchange interaction in the complexes. The observed value of coercive field (Hc) and remanent magnetization (Mr) at 4 K for the compound are 497 Oe and 1.03 Nβ. The presence of spin-glass behaviours in the compound is ascribed mainly to domain mobility or domain growth under different cooling conditions.