F. Onufrieva et J. Rossatmignod, DYNAMIC MAGNETIC-SUSCEPTIBILITY OF COPPER-OXIDE SUPERCONDUCTORS IN THE METALLIC STATE, Physica. B, Condensed matter, 199, 1994, pp. 344-346
The main features of the spin dynamics within CuO2-layers observed in
the YBa2Cu3O6+x system as a function of doping and temperature in the
metallic state with magnetic short-range order are well accounted for
by a theory based on the t-t'-J model and a slave-fermion approach. Im
chi(q, omega) looks like a two-spinon density of states and exhibits
a gap at low energy and a cut off at high energy, the uniform suscepti
bility vanishes at T = 0. The shape of Im chi(q, omega) as a function
of omega is T-dependent.