title: Magnon-enhanced phonon damping at Gd(0001) and Tb(0001) surfaces using femtosecond time-resolved optical second-harmonic generation.
abstract: Damping of coherent optical phonons is investigated by femtosecond time-resolved second-harmonic generation at Gd(0001) and Tb(0001) surfaces. At low temperature the damping rate increases monotonically with temperature, but close to the Curie point the damping rate is strongly reduced. We explain this behavior by phonon-magnon scattering originating from spin-orbit coupling proven by a larger effect for Tb than for Gd. Consideration of phonon-electron and phonon-phonon scattering shows that magnon-mediated damping is dominant almost up to the Curie temperature.
authors.affiliation: Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Melnikov
authors.forename: A
authors.initials: A
authors.lastname: Povolotskiy
authors.forename: U
authors.initials: U
authors.lastname: Bovensiepen