A layered cobalt phosphonate exhibiting ferrimagnetism and slow magnetic relaxation

Compound Co3(hpyedpH)2(H2O)4 · H2O (1) (hpyedpH4 = 1-hydroxy-2-(3-pyridyl)ethylidene-1,1-diphosphonic acid) has a layer structure where chains of {Co3(hpyedpH)2(H2O)4}n are connected by {CPO3} tetrahedra, generating a layer containing 4-, 8- and 16-membered rings. Magnetic measurements show that compound 1 is a ferrimagnet with Tc = 3.8 K. Slow magnetic relaxation is observed below 3.8 K, possibly due to the domain wall movement.