Quantum Spin‐ Dimers in a Low‐Dimensional Tetrabromocuprate Magnet

This work describes a homometallic spin ½ tetrabromocuprate adopting a bilayer structure. Magnetic susceptibility measurements show a broad maximum centered near 70 K, with fits to this data using a Heisenberg model consistent with strong antiferromagnetic coupling between neighboring Cu in different layers of the bilayer. There are further weak intralayer ferromagnetic interactions between Cu cations in neighboring dimers. First principles calculations are consistent with this but suggest there is only significant magnetic coupling within one direction of a layer; this would suggest the presence of a spin-ladder within the bilayer with antiferromagnetic rung and weaker ferromagnetic rail couplings.