Tailoring magnetic damping and anisotropy in bismuth-doped yttrium iron garnet (Bi 1 Y 2 Fe 5 O 12 ) thin films
Résumé
Bismuth-doped yttrium iron garnet (BiYIG) has attracted significant attention for magnonics and spintronics due to its perpendicular magnetic anisotropy and exceptionally low Gilbert damping. However, realizing BiYIG thin films with precisely tailored magnetic properties-including effective magnetization (M eff ), inhomogeneous linewidth broadening (µ0∆H0), and damping constant (α)requires careful optimization of the growth conditions. In this work, we report the growth and detailed characterization of BiYIG thin films deposited on (111)-oriented substituted gadolinium gallium garnet (sGGG) substrates by pulsed-laser deposition. High-quality films were obtained by varying the substrate temperature (420-510 • C) at fixed laser fluence (40 mJ), and by varying the fluence (30-55 mJ) at fixed temperature (495 • C).
For ∼ 20 nm-thick films, we achieved stoichiometric BiYIG with in situ x-ray photoelectron spectroscopy confirming the chemical integrity. Broadband ferromagnetic resonance measurements reveal an ultra-low damping constant of α ∼ 1.1 × 10 -4 , an effective magnetization of µ0M eff ∼ -7.1 mT, and inhomogeneous broadening as low as µ0∆H0 ∼ 0.9 mT. In selected samples, magnetooptical imaging further confirms the presence of stable magnetic bubble domains.
Overall, this work provides a practical methodology for reproducibly obtaining targeted magnetic properties in BiYIG thin films, including low damping, narrow linewidth, and tunable anisotropy, suitable for future magnonic and spintronic applications.
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