Magnetization dynamics of ferromagnetic rare earth metals induced by femtosecond laser excitation

• Applicant: Professor Dr. Uwe Bovensiepen
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2004 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5430780

The project aims at a fundamental understanding of ultrafast magnetization dynamics of rare earth ferromagnets (Gd, Tb, Dy) induced by femtosecond laser pulses. Time-resolved detection of second harmonic generation and two-photon-photoemission are employed as complementary experimental techniques to study the temporal evolution of the magnetic and non-magnetic optical response as well as the exchange-split electronic structure and electron distribution of heavy lanthanides. The magnetization dynamics on the Gd(0001) surface presents an ideal model system, which is governed by (a) incoherent scattering processes leading to relaxation of the photoexcited non-equilibrium electron/spin distribution and (b) coherent magnetization dynamics in the THz frequency range. Tb and Dy present promising systems as a test case for comparison. The goals of this project are: (i) Systematic study of ultrafast magnetization dynamics of heavy rare earth systems. (ii) Identification of spin-scattering mechanisms contributing to demagnetization within several 100 fs after the optical excitation and subsequent remagnetization probed in experiments as a function of temperature, excitation density and defect concentration. (iii) Detailed understanding of coherent magnetization dynamics in the THz domain including description of damping by appropriate elementary processes.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1133: Ultrafast magnetization processes
• Participating Person: Professor Dr. Martin Wolf