Gutenberg Open Science

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  • Item type: Item , ZeitschriftenaufsatzAccess status: Open Access ,
    Ultrafast dynamics of chiral spin structures in synthetic antiferromagnets
    (2025) Guo, Zongxia; Gruber, Raphael; Ksenzov, Dmitriy; Léveillé, Cyril; Pancaldi, Matteo; Pedersoli, Emanuele; Spezzani, Carlo; De Ninno, Giovanni; Capotondi, Flavio; Gutt, Christian; Kläui, Mathias; Cros, Vincent; Reyren, Nicolas; Jaouen, Nicolas
    In synthetic antiferromagnetic multilayers (SAFs), chiral magnetic structures such as spin spirals and skyrmions have been stabilized at room temperature by precisely tuning the effective perpendicular magnetic anisotropy, the Dzyaloshinskii-Moriya interaction, and the Ruderman-Kittel-Kasuya-Yoshida (RKKY) interlayer coupling. In this study, we investigate the dynamics of spin spirals on ultrashort timescales after femtosecond laser pumping in SAFs. The access to ultrafast magnetization dynamics, inaccessible by conventional optical techniques due to the zero net magnetization, has been enabled by the use of time-resolved circular dichroism in x-ray resonant magnetic scattering (CD-XRMS). A pair of two-dimensional x-ray scattering patterns for left and right elliptical polarization (EL and ER) have been recorded for each delay. In contrast to our previous findings in ferromagnetic multilayers, the magnetization (EL+ER) and dichroism (EL−ER) signals exhibit notably similar ultrafast dynamics, with demagnetization occurring on a timescale of ∼180 fs, followed by rapid remagnetization within ∼500 fs. This similarity in ultrafast dynamics can be attributed to the continuous rotation of magnetization in the spin spiral of SAFs, which evolves smoothly in space without forming abrupt domains or alternating domain walls. The ultrafast response and stability in its topological character highlight the potential of SAF-based chiral magnetic structures for future high-speed, energy-efficient data storage and processing applications.
  • Item type: Item , ZeitschriftenaufsatzAccess status: Open Access ,
    Identifying switching of antiferromagnets by spin-orbit torques
    (2025) Jourdan, Martin; Bläßer, Jonathan; Orero Gámez, Guzmán; Reimers, Sonka; Odenbreit, Lukas; Fischer, Miriam; Niu, Yuran R; Golias, Evangelos; Maccherozzi, Francesco; Kleibert, Armin; Stoll, Hermann; Kläui, Mathias
    Antiferromagnets are promising candidates for ultrafast spintronic applications, leveraging current-induced spin-orbit torques. However, experimentally distinguishing between different switching mechanisms of the staggered magnetization (Néel vector) driven by current pulses remains a challenge. In an exemplary study of the collinear antiferromagnetic compound Mn2⁢Au, we demonstrate that slower thermomagnetoelastic effects predominantly govern switching over a wide parameter range. In the regime of short current pulses in the nanosecond range, however, we observe fully Néel spin-orbit torque driven switching. We show that this ultrafast mechanism enables the complete directional alignment of the Néel vector by current pulses in device structures.
  • Item type: Item , ZeitschriftenaufsatzAccess status: Open Access ,
    Temperature-dependent study of the spin dynamics of coupled Y3Fe5O12/Gd3Fe5O12/Pt trilayers
    (2025) Fuhrmann, Felix; Becker, Sven; Akashdeep, Akashdeep; Jakob, Gerhard; Lan, Qianqian; Wang, Nan; Dunin-Borkowski, Rafal E.; Lebrun, Romain; Weiler, Mathias; Kläui, Mathias
    We combine ferromagnetic resonance absorption measurements (FMR) with spin pumping measurements to ascertain the full magnetization dynamics of Y3⁢Fe5⁢O12 (YIG)/Gd3⁢Fe5⁢O12 (GdIG)/Pt heterostructures. This trilayer system offers the unique possibility to individually investigate the spin dynamics of the ferrimagnetic GdIG close to its compensation temperature. We show that this trilayer acts as a highly tunable spin current source and our experimental results are corroborated by micromagnetic simulations. The detected spin current in the top Pt layer is governed by spin dynamics in the GdIG layer, while the broadband FMR absorption spectrum of the full heterostructure comprises contributions from spin dynamics in both layers. Thus, combining the measurements of FMR absorption and spin current generation from the spin pumping and spin Seebeck effect allows us to understand the spin dynamics contributions of both constituents.