Neutron-Diffraction Evidence for the Ferrimagnetic Ground State of a Molecule-Based Magnet with Weakly Coupled Sublattices

Abstract

The diruthenium compound [Ru2(O2CMe)4]3[Cr(CN)6] contains two weakly coupled, ferrimag- netically ordered sublattices occupying the same volume. The magnetic field Hc ≈ 800 Oe required to align the two sublattice moments is proportional to the antiferromagnetic dipolar interaction Kc ∼ μB Hc ≈ 5 × 10−3 meV between sublattices. Powder neutron-diffraction measurements on a deuterated sample reveal that the sublattice moments are restricted by the anisotropy of the diruthenium “paddle-wheel” complexes to the cubic diagonals. Those measurements also suggest that the quantum corrections to the ground state are significant.