E. Romero, M. E. Mendoza and R. Escudero
Oxalate dihydrates containing divalent 3d transition elements exhibit quasi-one-dimensional (quasi-1D) magnetic behavior characterized by a dominant magnetic correlation along the oxalate—metal-ion chains. Recently, a weak antiferromagnetic (AF) interaction in these compounds has been reported. However, it was argued that in such systems the intra- and inter-chain magnetic interactions will cant the spins, distorting the antiferromagnetic order and producing also a weak ferromagnetism (WF), presumably more pronounced at low temperatures. Cobalt oxalate dihydrate is a quasi-1D magnetic compound useful for searching for the existence of WF at low temperature. On pp. 1519–1525, E. Romero, M. E. Mendoza and R. Escudero report their results on the synthesis, crystal structure, and magnetic measurement of the orthorhombic β-CoC2O4.2O microcrystals. Their magnetic measurements show the existence of an uncompensated canted antiferromagnetism. Thus the magnetic ordering gives rise to weak ferromagnetism. From M—H measurements at 2–200 K, it was determined that WF ordering is exhibited at T < 7.5 K.