THz-Driven Ultrafast Spin-Lattice Scattering in Amorphous Metallic Ferromagnets
Number of Authors: 8
2016 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 117, no 8, 087205Article in journal (Refereed) Published
We use single-cycle THz fields and the femtosecond magneto-optical Kerr effect to, respectively, excite and probe the magnetization dynamics in two thin-film ferromagnets with different lattice structures: crystalline Fe and amorphous CoFeB. We observe Landau-Lifshitz-torque magnetization dynamics of comparable magnitude in both systems, but only the amorphous sample shows ultrafast demagnetization caused by the spin-lattice depolarization of the THz-induced ultrafast spin current. Quantitative modeling shows that such spin-lattice scattering events occur on similar time scales than the conventional spin conserving electronic scattering (similar to 30 fs). This is significantly faster than optical laser-induced demagnetization. THz conductivity measurements point towards the influence of lattice disorder in amorphous CoFeB as the driving force for enhanced spin-lattice scattering.
Place, publisher, year, edition, pages
2016. Vol. 117, no 8, 087205
IdentifiersURN: urn:nbn:se:su:diva-134422DOI: 10.1103/PhysRevLett.117.087205ISI: 000381496400007PubMedID: 27588880OAI: oai:DiVA.org:su-134422DiVA: diva2:1037228