Magnetic properties of a metal-organic chain system [Co(bpdc)(H2O)2]∙H2O (bpdc=biphenyldicarboxylate)

The magnetic properties of a recently discovered metal-organic magnetic chain compound, [Co(bpdc)(H2O)2]∙H2O, were investigated using measurements of magnetic susceptibility M(T)∕H, isothermal magnetization M(H), and heat capacity C(T). The room temperature crystal structure of [Co(bpdc)(H2O)2]∙H2O is monoclinic, space group C2∕c, with lattice parameters a=6.950A, b=31.585A, c=6.226A, and β=95.84°. The M(T)∕H data above 40K were fit to Curie–Weiss law with an effective moment of 5.37μB and a Curie–Weiss temperature of +26K. A spontaneous antiferromagnetic ordering with a transition temperature of 5.5K was observed in the low field M(T)∕H data. In addition, a metamagnetic transition at 500G was found in M(H), measured at 2K. The sizable anomaly observed in C(T) confirms the magnetic phase transition and the transition temperature. The total magnetic entropy removal at 5.5K is 800mJ∕molK. The nature of the magnetic properties is discussed in terms of the ferromagnetic intrachain exchange interaction between...