Two dimensional ordering and fluctuations in alpha(')-NaV2O5

X-ray diffraction measurements of Bragg and diffuse scattering associated with charge ordering in the inorganic compound alpha(')- NaV2O5 show a continuous phase transition at a temperature of about 33.1 K. Many of this material's properties suggest a spin-Peierls transition, as established in CuGeO3 and MEM(TCNQ)(2). We compare the order parameter as well as fluctuations in the order parameter in these materials, and conclude that alpha(')- NaV2O5 is dissimilar, and that the transition is two dimensional in nature, due to charge ordering associated with the fractional average valence at the vanadium site within the orthorhombic a- b plane.

Charge-order-driven spin-peierls transition in alpha(')-NaxV2O5

We conclude from 23Na and 51V NMR measurements in alpha(')-NaxV2O5 (x = 0.996) (i) a charge-ordering transition starting at T