Mean field analysis of the exchange coupling (J) for two- and three-dimensional structured tetracyanoethenide (TCNE ^•-)-based magnets

Mean field expressions based on the simple Heisenberg model were derived to correlate the inter- and intralayer exchange couplings to the critical temperatures, T _c, for several tetracyanoethylene (TCNE)-based magnets with extended two- and three-dimensional (2-D and 3-D) structure types. These expressions were used to estimate the exchange coupling, J, for 2-D ferrimagnetic [M ^II(TCNE)(NCMe) ₂] ⁺ (M = Mn, Fe), 3-D antiferromagnetic Mn ^II(TCNE)[C ₄(CN) ₈] _1/2, and 3-D ferrimagnetic Mn ^II(TCNE) _3/2(I ₃) _1/2. The type and magnitude of the exchange coupling are in accord with the previously reported magnetic data.