Ferromagnetic behavior of decamethylchromocenium tetracyanoethanide [CrCp2][TCNE]

Studies on the magnetic properties of decamethylchromocenium tetracyanoethanide, [CrCp*2][TCNE] are reported herein. Near-zero field (H=150 mG) data indicates a ferromagnetic transition with Tc=3.65 K. The temperature dependence below Tc can be fit to a mean-field result M=M0(1−T/Tc)1/2, and the data above Tc gives a critical exponent γ=1.2 for the dc magnetic susceptibility. Data at higher temperature indicates a strong 1-D ferromagnetic behavior. Magnetizations at different H and T at low temperature can be scaled to a universal function with M=f(H/T3.2). The reduction in Tc in [CrCp*2][TCNE] compared with [FeCp*2][TCNE] indicates a competition between the coupling constants and the residing spins.