Abstract
The compound has been studied by spectroscopy in the IR, near-infrared, and visible regions. X-ray and neutron diffraction indicate two-dimensional (2D) structural order of magnetic ions on a honeycomb lattice with nonmagnetic ions complementing the hexagonal layer. Superstructure reflections observed by neutron diffraction reveal the presence of this 2D structural Cu/V order in domains of approximately with a disordered stacking along the axis. Specific-heat, thermal-expansion, and neutron-diffraction experiments gave no signs of a three-dimensional long-range magnetic order. Strong 2D magnetic correlations seem to persist down to low temperatures, providing evidence of an incipient Néel-type ground state on this hitherto rarely studied lattice geometry in . Magnetic correlations in these structural domains are compared with continuous time quantum-Monte Carlo calculations of the specific heat and in particular of the spin-spin-correlation length.
4 More- Received 5 March 2008
DOI:https://doi.org/10.1103/PhysRevB.78.024420
©2008 American Physical Society