Spin Dynamics of Sr14Cu24O41 Two-Leg Ladder Studied by Raman Spectroscopy
05 November 2001
The two-magnon (2M) excitation at 3000 cm21 in Sr14Cu24O41 two-leg ladder is studied by Raman scattering. A slight anisotropy of the superexchange coupling JXXJk X 0.8 with Jk X 110 6 20 meV is proposed from the analysis of the magnetic scattering. The resonant coupling across the charge transfer gap increases the 2M intensity by orders of magnitude. The anisotropy of Raman scattering is dependent upon the excitation energy. The 2M relaxation is found to be correlated with the temperature dependent electronic Raman continuum at low frequencies.