We examined the photo-induced dynamics of ferromagnetic Co/Pt thin films demonstrating perpendicular magnetic anisotropy with element specificity using resonant polar magneto-optical Kerr effect measurements at Pt~N6,7 and Co~M2,3 edges with an x-ray free electron laser. The obtained results showed a clear element dependence of photo-induced demagnetization time scales: τdemag.Co=80±60fs and τdemag.Pt=640±140fs. This dependence is explained by the induced moment of the Pt atom by current flow from the Co layer through the interfaces. The observed magnetization dynamics of Co and Pt can be attributed to the characteristics of photo-induced Co/Pt thin film phenomena including all-optical switching.
@article{arxiv.1910.01556,
title = {Element-selective tracking ultrafast demagnetization process in Co/Pt multilayer thin films by the resonant magneto-optical Kerr effect},
author = {Kohei Yamamoto and Souliman El Moussaoui and Yasuyuki Hirata and Susumu Yamamoto and Yuya Kubota and Shigeki Owada and Makina Yabashi and Takeshi Seki and Koki Takanashi and Iwao Matsuda and Hiroki Wadati},
journal= {arXiv preprint arXiv:1910.01556},
year = {2020}
}