Decoupled magnetic transitions in layered bimetallic composites

The layered bimetallic magnet ferrocenium tetrachloroferrate [FeCp(2)][FeCl4], has been shown to act as a composite material with separate cation and anion sublattice ordering temperatures through a combination of low field dc and ac susceptibility measurements as well as zero-field Mossbauer spectroscopy. While the anion sublattice orders near 4.2 K, the cation sublattice remains paramagnetic down to 3.8 K, a relative shift of ordering temperature of nearly ten percent. Each sublattice orders in a three-dimensional antiferromagnetic state for which there is no absorbtion in the ac-susceptibility.