Magnetic excitations of single-crystal PrBa2Cu3O6.2

Measurements of the low-energy magnetic excitations in single-crystal PrBa2 Cu3O6.2, and in YBa2Cu3O6.2 for comparison, have been performed using inela stic neutron scattering. An excitation with weak dispersion is seen, which is compared to a spin-wave model based on the lowest lying crystal field le vels of the Pr ion, and including the effect of an anisotropic coupling to the Cu magnetic moments, as well as a Pr-Pr exchange interaction. (C) 2000 Elsevier Science B.V. All rights reserved.