Ultrafast perturbation of magnetic domains by optical pumping in a ferromagnetic multilayer

Published

October 19, 2022

Author(s)

Dmitriy Zusin, Ezio E. Iacocca, Loic Le Guyader, Alexander H. Reid, William Schlotter, TianMin Liu, Daniel Higley, Giacomo Coslovich, Scott F. Wandel, Phoebe Tengdin, Sheena K. Patel, Anatoly Shabalin, Nelson Hua, Stjepan Hrkac, Hans Nembach, Justin Shaw, Sergio Montoya, Adam Blonsky, Christian Gentry, Mark Hoefer, Margaret M. Murnane, Henry C. Kapteyn, Eric E. Fullerton, Oleg Shpyrko, Hermann Durr, Thomas J. Silva

Abstract

Ultrafast optical pumping of spatially nonuniform magnetic textures is known to induce far-from-equilibrium spin transport effects. Here, we use ultrafast x-ray diffraction with unprecedented dynamic range to study the laser-induced dynamics of labyrinth domain networks in ferromagnetic CoFe/Ni multilayers. We detected azimuthally isotropic, odd order, magnetic diffraction rings up to fifth order. The amplitudes of all three diffraction rings quench to different degrees within 1.6 ps. In addition, all three of the detected diffraction rings both broaden by 15% and radially contract by 6% during the quench process. We are able to rigorously quantify a 31% ultrafast broadening of the domain walls via Fourier analysis of the order-dependent quenching of the three detected diffraction rings. The broadening of the diffraction rings is interpreted as a reduction in the domain coherence length, but the shift in the ring radius, while unambiguous in its occurrence, remains unexplained. In particular, we demonstrate that a radial shift explained by domain-wall broadening can be ruled out. With the unprecedented dynamic range of our data, our results provide convincing evidence that labyrinth domain structures are spatially perturbed at ultrafast speeds under far-from-equilibrium conditions, albeit the mechanism inducing the perturbations remains yet to be clarified.

Citation

Physical Review B

Volume

106

Pub Type

Journals

Download Paper

https://doi.org/10.1103/PhysRevB.106.144422

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Keywords

ultrafast optical pumping, spatially nonuniform magnetic textures, far-from-equilibrium, spin transport effects, broadening of domain-walls, labyrinth domain networks, ferromagnetic CoFe/Ni multilayers, femtosecond optical pump, ultrafast domain dilation, magnetic X-ray diffraction, quasi-ballistic, inelastic electron-magnon scattering, spin textures

Citation

Zusin, D. , Iacocca, E. , Guyader, L. , Reid, A. , Schlotter, W. , Liu, T. , Higley, D. , Coslovich, G. , Wandel, S. , Tengdin, P. , Patel, S. , Shabalin, A. , Hua, N. , Hrkac, S. , Nembach, H. , Shaw, J. , Montoya, S. , Blonsky, A. , Gentry, C. , Hoefer, M. , Murnane, M. , Kapteyn, H. , Fullerton, E. , Shpyrko, O. , Durr, H. and Silva, T. (2022), Ultrafast perturbation of magnetic domains by optical pumping in a ferromagnetic multilayer, Physical Review B, [online], https://doi.org/10.1103/PhysRevB.106.144422, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=929420 (Accessed December 22, 2024)