Aluminum‐Substituted Yttrium Iron Garnet Films With Perpendicular Anisotropy Grown on Silicon by Sputtering

ABSTRACT Rare‐earth iron garnets (REIGs) are key materials in spintronics due to their low magnetic damping and tunable magnetic anisotropy. While ultrathin REIG films with perpendicular magnetic anisotropy (PMA) have been successfully grown on single‐crystal garnet substrates, their integration with silicon remains a critical challenge for scalable spintronic technologies. This work reports the comprehensive characterization of thin yttrium iron garnet (YIG) films sputter‐grown on amorphous Si/ substrates using an ultrathin buffer layer. Al is found to diffuse into the nominally YIG structure, predominantly substituting Fe, reducing the saturation magnetization, and ultimately leading to PMA. Electrical and optical characterization of Al:YIG/Pt bilayers reveals pronounced spin Hall magnetoresistance (SMR) and efficient spin–orbit torque (SOT) switching, including multistate switching behavior mimicking an analog behavior. These findings demonstrate the feasibility of integrating archetypal YIG with silicon platforms and highlight its potential for energy‐efficient, multistate spintronic devices in neuromorphic computing and reconfigurable logic applications.