Ultrafast optical excitation of gold-cobalt bilayers triggers the nontrivial interplay between the electronic, acoustic, and magnetic degrees of freedom. Laser-heated electrons generated at the gold-air interface diffuse through the layer of gold and strongly overheat the lattice in cobalt resulting in the emission of ultrashort acoustic pulses and generation of exchange-coupled magnons. Time-resolved optical measurements allow for extracting the thermal boundary (Kapitza) resistances at metal/metal interfaces and the hot electron diffusion length in ferromagnetic materials. Both the experimental data and the analytical treatment of the two-temperature model reveal the role of the Kapitza resistance in transient lattice overheating.
@article{arxiv.1511.09060,
title = {Ultrafast electron-phonon-magnon interactions at noble metal-ferromagnet interfaces},
author = {V. Shalagatskyi and O. Kovalenko and V. Shumylo and A. Alekhin and G. Vaudel and T. Pezeril and V. S. Vlasov and A. M. Lomonosov and V. E. Gusev and D. Makarov and V. V. Temnov},
journal= {arXiv preprint arXiv:1511.09060},
year = {2017}
}