Speaker
Description
Iron garnets, particularly yttrium iron garnet (YIG) and doped variants, are crucial materials for spintronic applications due to their exceptionally low damping ($\alpha \approx 10^{-5}$), high spin-wave propagation lengths, and tunable magnetic properties [1]. Understanding their magnetization dynamics in thin-film and heterostructure configurations is essential for advancing their integration into next-generation spintronic devices [2, 3].
In this study, we investigate the magnetization dynamics of Y$_3$Fe$_5$O$_{12}$ thin films and heterostructures using a combination of ferromagnetic resonance (FMR), magneto-optical Kerr effect (MOKE) microscopy, and Brillouin light scattering (BLS) spectroscopy. High-quality epitaxial iron garnet films were grown on lattice-matched substrates and characterized for structural and magnetic properties. FMR measurements were performed to extract key dynamical parameters, including Gilbert damping, in-plane anisotropy, inhomogeneous line broadening. The results reveal a strong dependence of damping and resonance field on film thickness, composition, and interface effects, particularly in heterostructures with Tm$_3$Fe$_5$O$_{12}$. MOKE microscopy enabled spatially resolved studies of magnetic domain and spin textures. BLS spectroscopy provided insights into spin-wave dispersion and lifetime, highlighting the interfacial induced Dzyaloshinskii-Moriya interaction (DMI) in asymmetric heterostructures.
Our findings offer a comprehensive understanding of the dynamic properties of iron garnet thin films and their heterostructures, paving the way for their optimized use in magnonics, nonvolatile memory, and spin-orbit torque-based devices.
Acknowledgements
We acknowledge the financial support from PATTERN (G. A. :No 101070506) and DEMURGE (Projet-ANR-22-CE30-0014).
References
[1] V. Cherepanov et al., “The saga of YIG: Spectra, thermodynamics, interaction and relaxation of magnons in a complex magnet,” Physics Reports, vol. 229, no. 3. Elsevier BV, pp. 81–144, Jul. 1993. https://doi.org/10.1016/0370-1573(93)90107-o
[2] Y. Fan et al., “Coherent magnon-induced domain-wall motion in a magnetic insulator channel,” Nature Nanotechnology, vol. 18, no. 9. Springer Science and Business Media LLC, pp. 1000–1004, Jun. 01, 2023. https://doi.org/10.1038/s41565-023-01406-2
[3] T. Fakhrul et al., “Damping and Interfacial Dzyaloshinskii–Moriya Interaction in Thulium Iron Garnet/Bismuth-Substituted Yttrium Iron Garnet Bilayers,” ACS Applied Materials & Interfaces, vol. 16, no. 2. American Chemical Society (ACS), pp. 2489–2496, Jan. 05, 2024. https://doi.org/10.1021/acsami.3c14706
