Magnetic field effects in decamethyl ferrocenium tetracyanoethanide

Abstract The specific heat C ( H , T ) of (DMeFc) (TCNE) in the temperature range of 2–12 K in the presence of applied magnetic fields is reported. Previous results had shown anomaly at 4.82 K corresponding to a transition at T c from a high temperature one-dimensional (1D) magnet (above T c ) to a three-dimensional (3D) macroscopic ferromagnet (below T c ). The results show a dramatic behavior of the peak associated with the ferromagnetic transition. The peak height decreases with increasing magnetic field, i.e. magnetic fields smear the transition. For small values of applied magnetic fields the peak associated with the ferromagnetic transition is completely smeared. The results are indicative of anisotropic chains with enhanced 1D coherence and frustration in interchain coupling. The spin-wave spectrum is dominated by the 1D chains below T c.