Q-DEPENDENCE OF THE DYNAMIC SUSCEPTIBILITY CHI''(Q,OMEGA) IN SUPERCONDUCTING YBA2CU3O6.6 (T-C=46-K)

q-dependent neutron-scattering measurements of the dynamic susceptibil ity chi''(q,omega) in superconducting YBa2CU3O6.6 are presented. The o bserved magnetic scattering near the antiferromagnetic zone center has a nontrivial, approximately flat-topped q dependence. A separable mod el of the susceptibility, chi''(q,omega)=chi''(omega)F(q), is found to describe this scattering at all energies in the range 2 meV less than or equal to ($) over bar h omega less than or equal to 40 meV. Measur ements at temperatures above and below T-c=46 K indicate that the q-de pendent ''shape'' function, F(q), is the same in both the superconduct ing and normal states. A phenomenological expression for F(q) is prese nted and the physical significance of its parametrization is discussed . These results are compared with current theories in the literature.