The exceptional magnetic, optical and phononic properties of Yttrium Iron Garnet (YIG) make it unique for spin-wave based and photonic applications. Yet, nanostructuring crystalline YIG and manipulating its magnetism in a non-destructive way is an outstanding challenge, and so far mostly limited to two-dimensional capabilities. Here, we show that irradiation of single-crystal YIG films with a focused UV laser drives a stable, giant enhancement of the perpendicular magnetic anisotropy, preserving the crystalline quality. This modulation is highly confined at the nanoscale in both the lateral and vertical directions, and its extension within the volume can be finely tuned with a continuous depth-control. By harnessing these three-dimensional anisotropy profiles, we demonstrate a large tuning of the spin-wave band structure, volume spatial localization, and non-reciprocity, realizing proof-of-principle 3D magnonic crystals. This straightforward, single-step, laser nanofabrication of three-dimensional magnetic systems based on crystalline YIG thin films opens the way to design novel functions in magnonic and magneto-optic devices.
@article{arxiv.2409.17722,
title = {Three-dimensional nanoscale control of magnetism in crystalline Yttrium Iron Garnet},
author = {Valerio Levati and Matteo Vitali and Andrea Del Giacco and Nicola Pellizzi and Raffaele Silvani and Luca Ciaccarini Mavilla and Marco Madami and Irene Biancardi and Davide Girardi and Matteo Panzeri and Piero Florio and Maria Cocconcelli and David Breitbach and Philipp Pirro and Ludovica Rovatti and Nora Lecis and Federico Maspero and Riccardo Bertacco and Giacomo Corrielli and Roberto Osellame and Valeria Russo and Andrea Li Bassi and Silvia Tacchi and Daniela Petti and Edoardo Albisetti},
journal= {arXiv preprint arXiv:2409.17722},
year = {2025}
}