Resonant magnon Raman scattering in PrBa2Cu3O7 single crystals

We present resonant Raman spectra of spin excitations in PrBa2Cu3O7 single crystals up to a 10000 cm(-1) Raman shift in an A(1g) and B-1g polarization geometry. In accordance with the theory of resonant two-magnon scattering by Chubukov and Frenkel [Phys. Rev. Lett. 74, 3057 (1995)] we find a separate peak at 4J in the A(1g) spectra near resonance and the predicted resonance behavior of the peak at 3J in B-1g symmetry as well as an increased scattering intensity in A(1g) symmetry. The superexchange energy J is (770+/-20) cm(-1) and the resonance position of the two-magnon excitation is 2.79 eV. We observe a distinct high-energy tail extending up to 10J, which is most likely due to multimagnon processes. Moreover, an additional peak can be attributed to a luminescence at an energy of 2.14 eV.