The magnetic behaviour of the coordination polymer [Co(C3H3N2)2]n has been investigated by magnetization and specific heat measurements. Low-field magnetic susceptibility shows the presence of two maxima at approximately 8 and 4 K (Tf), which reflect short-range low-dimensional antiferromagnetic behaviour and the existence of a spin-glass-like state, respectively. The latter state was observed by magnetic irreversibility in both the zero-field cooled and field-cooled data, and was also confirmed by specific heat measurements. The magnetic specific heat (Cmag) shows a lack of any long-range ordered peaks. Instead, a broad maximum near Tf was observed in the Cma)(T)/T-curve. Below Tf, the Cmag(T) data follow the relation: Cmag(T)/T = gamma + AT. We suggest that the competition of the antiferromagnetic (AF) intra-chain and the ferromagnetic (F) inter-chain interactions in a low-dimensional arrangement of magnetic Co2+ ions can produce the spin-glass behaviour in the sample. The susceptibility data was analyzed in terms of a spin S = 3/2 Heisenberg linear-chain model with a small exchange energy and is consistent with the presence of both F and AF interactions. The splitting of the crystal field energy levels of the Co2+ ions causes a Schottky-type specific heat anomaly of around 60 K.
We report on a detailed investigation of magnetic susceptibility χ (T, B), magnetization M(T, B) and specific heat Cp(T, B) for a polycrystalline sample of Co(C3H4N2)2(CO3)(H2O)2. Ground state for Co2+ has found to show an unquenched spin–orbit coupling and a weak antiferromagnetic interaction between Co ions. Application of magnetic field significantly affects the magnetization and specific heat at T < 20 K. Anomaly observed in Cp(T, H)‐dependences may be interpreted in terms of the conventional two‐level (doublet–singlet) Schottky model. Both energy gap between these levels and the coefficient of the electronic specific heat are strongly field dependent.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.