Ultra-low damping insulating magnetic thin films get perpendicular.

Soumah, Lucile; Beaulieu, Nathan; Qassym, Lilia; Carrétéro, Cécile; Jacquet, Eric; Lebourgeois, Richard; Ben Youssef, Jamal; Bortolotti, Paolo et al. · Nat Commun · 2018

basic_science · Level V

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Abstract

A magnetic material combining low losses and large perpendicular magnetic anisotropy (PMA) is still a missing brick in the magnonic and spintronic fields. We report here on the growth of ultrathin Bismuth doped Y<sub>3</sub>Fe<sub>5</sub>O<sub>12</sub> (BiYIG) films on Gd<sub>3</sub>Ga<sub>5</sub>O<sub>12</sub> (GGG) and substituted GGG (sGGG) (111) oriented substrates. A fine tuning of the PMA is obtained using both epitaxial strain and growth-induced anisotropies. Both spontaneously in-plane and out-of-plane magnetized thin films can be elaborated. Ferromagnetic Resonance (FMR) measurements demonstrate the high-dynamic quality of these BiYIG ultrathin films; PMA films with Gilbert damping values as low as 3 × 10<sup>-4</sup> and FMR linewidth of 0.3 mT at 8 GHz are achieved even for films that do not exceed 30 nm in thickness. Moreover, we measure inverse spin hall effect (ISHE) on Pt/BiYIG stacks showing that the magnetic insulator's surface is transparent to spin current, making it appealing for spintronic applications.