Speaker
Description
The studies of spin injection across ferromagnetic/metallic interfaces are currently areas of interest, as the potential of layered structures being the basic building blocks of spintronic devices [1]. In technological applications one would like to have spin injection without spin-flip, therefore it is important to understand the microscopic nature of spin polarized transport and spin-flip at the interfaces.
In this work we report the experimental (time-resolved magnetization induced second harmonic generation [2]) and theoretical studies (time-dependent density functional theory [3]) at Co/Cu(001) interfaces. With the agreement between theory and experiment we identify a spin polarized transport from Co majority to Cu during the first 30 fs after optical excitation. Moreover the theory implies a simultaneous spin transfer from Cu minority to Co due to 1.55 eV pumping energy. Both experimental and theoretical data show that magnetization dynamics reaches its maximum change at 100 fs, in which the spin-orbit coupling changes the magnetization at time delays later than the saturation of the dynamics induced by charge transfer across the interface (30 fs). In conclusion we show that spin-flip processes can be induced by spin-orbit coupling without involving other scattering processes [4], which opens new possibilities for ultrafast control of spin dynamics.
We acknowledge funding from the DFG through SPP 1840.
[1] C. Chappert, A. Fert, and F. N. Van Dau, Nat. Mater. 6, 813 (2007).
[2] J. Chen, J. Wieczorek, A. Eschenlohr, S. Xiao, A. Tarasevitch, and U. Bovensiepen, Appl. Phys. Lett. 110, 092407 (2017).
[3] K. Krieger, J. K. Dewhurst, P. Elliott, S. Sharma, and E. K. U. Gross, J. Chem. Theory Comput. 11, 48704 (2015).
[4] B. Koopmans, G. Malinowski, F. Dalla Longa, D. Steiauf, M. Fahnle, T. Roth, M. Cinchetti, and M. Aeschlimann, Nat. Mater. 9, 259 (2010).
