Séminaire/Seminar – nm thick Bismuth substituted Yttrium Iron Garnet films and their applications – Lucile Soumah – 17/10/22

Date/heure-Date/Time
Date(s) - 17/10/2022
14 h 00 min

Emplacement/Place
INSP - Sorbonne Université

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Salle de conférences de l’INSP – 22-23 salle 317

Lucile Soumah – CEA-Spintec – Grenoble

 

Abstract

Magnetic insulators are materials of choice when it comes to spin dynamics as they usually exhibit lower magnetic losses than their conducting counterparts. This enables long distance spin wave propagation and efficient spin transfer torque. Ultrathin (nm thick) Yttrium Iron Garnet (YIG) films with low enough losses and thickness have been used to observe various magnon spintronic effects such as current induced generation of auto oscillations or spin wave propagation [1].
However, due to shape anisotropy and low spin orbit coupling, YIG films remain in plane magnetized which brought limitations in terms of their applications for magnon-spintronic. In that regard, out-of-plane magnetized ultrathin magnetic insulators with low magnetic losses were, for a while, a need for magnon-spintronic applications. Moreover, light-based detection techniques (such as Brillouin Light scattering), commonly used to image spin dynamics in insulators, were suffering of the low magneto-optical coefficient in those in-plane magnetized YIG films which made detection with such experimental set up long and tedious.
In this seminar we present the growth of nanometer thick, Bismuth doped YIG films by pulsed laser deposition technique. In those ultrathin films we could achieve high Faraday rotation and perpendicular magnetic anisotropy while keeping magnetic losses comparable to the undoped YIG thin films [2]. We show how this new material has been proven to be attractive for the field of magnons spintronics [3] and light induced magnetization dynamics [4].

[1] Collet, Martin, et al. « Generation of coherent spin-wave modes in yttrium iron garnet microdiscs by spin–orbit torque. » Nature communications 7.1 (2016): 1-8.
[2] Soumah, Lucile, et al. « Ultra-low damping insulating magnetic thin films get perpendicular. » Nature communications 9.1 (2018): 1-6.
[3] Evelt, M., et al. « Emission of coherent propagating magnons by insulator-based spin-orbit-torque oscillators. » Physical Review Applied 10.4 (2018): 041002
[4] Soumah, Lucile, et al. « Optical Frequency Up-Conversion of the Ferromagnetic Resonance in an Ultrathin Garnet Mediated by Magnetoelastic Coupling. » Physical Review Letters 127.7 (2021): 077203