In the inorganic spin-Peierls compound CuGeO3, we found a pronounced anisotropic magnetic energy dispersion, i.e. intra-chain exchange Jc ≈ 10.4 meV, inter-chain exchanges Jb ≈ 0.1 Jc and Ja ≈ - 0.01Jc and gap energy 2.1 meV extrapolated to T = 0 K. We also observed critical scattering at (0, 1, 1/2) above Tsp. The ratio of the correlation lengths ξc/ξb is in good agreement with that obtained from X-ray scattering at (1/2, 1, 1/2) by Pouget et al. This fact suggests that the Cu2+ spins fluctuate to form singlet-pair short-range order, but not to form ordinary antiferromagnetic order above Tsp.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering