3D Long-Range Magnetic Ordering in Layered Metal–Hydroxide Triangular Lattices 25 ? Apart

The synthesis, characterization, and magnetic properties of the layered compounds, Cu2(OH)3(C12H25SO3)·H2O, Ni2(OH)3 (C12H25SO3)·H2O, and Co5(OH)8(C12H25SO3)2·5H2O, with a triangular magnetic lattice are reported. The interlayer distances are 23.8 (Cu), 23.0 (Ni), and 25.8 ? (Co). Long-range ferromagnetic (Ni) and ferrimagnetic (Co) ordering are observed with Curie temperatures of 18 (Ni) and 50K (Co). The coercive fields are 400 (Ni) and 19,000 Oe (Co), the latter being among the hardest metal–organic magnets. The long-range ordering is interpreted as being due to dipolar interaction between layers with large effective moments as a consequence of precursor short-range intralayer interactions. The large coercive field is interpreted as resulting from a synergy of crystalline shape, surface, and single ion anisotropies.