Magnetic Properties of the New Low Dimensional Fluoride Compound NaCuF₃

Experimental work on a physical realization of the Hubbard model NaCuF₃ has been carried out inspired by recent theoretical calculation. Large quantities of NaCuF₃ single crystals have been successfully synthesized and characterized. The experiments have suggested that rather than a single-band Hubbard model, this fluoride compound forms low-dimensional quantum Heisenberg system with the superexchange pathway going through corner-sharing CuF6 octahedra and an exchange strength about 17 meV. Single crystal neutron diffraction experiments indicate a long range magnetic ordering at 18.85(1) K and excitation spectra revealed by recent inelastic neutron scattering experiment has shown a two-spinon continuum at low temperature, characteristic of isolated antiferromagnetic Heisenberg spin chain.