Spin Transport in Epitaxial Lu₃Fe₅O₁₂ Garnet Films

Ferrimagnetic insulator (FMI) and heavy metal (HM) heterostructures are attracting significant interest in the field of spintronics due to the unique combination of properties they offer. FMIs exhibit low magnetic damping and robust spin filtering, while HMs provide high spin-orbit coupling, facilitating efficient spin current generation and manipulation. Systems exhibiting spin-orbit torque (SOT) effects coupled with perpendicular magnetic anisotropy (PMA) are particularly desirable for technological applications, as they enable higher bit densities [1]. While extensive research has been conducted on SOT switching in PMA ferromagnetic metals (e.g., Co, CoFeB), similar studies employing oxide ferro/ferri-magnetic materials are scarce [2]. Oxide ferro/ferri-magnetic materials offer two main advantages: favorable scaling behavior and the prevention of current shunting from the SOT-producing HM layer, as PMA is a bulk property rather than an interfacial one [3]. <br/> <br/>In this study, we report on the growth, structural, and magnetic properties of rare-earth lutetium iron garnet (Lu3Fe5O12, LuIG) thin films deposited on Gd3Ga5O12 (GGG) substrates oriented along the (111) direction. The films were grown using a pulsed laser deposition technique (248-nm KrF laser). High-resolution X-ray diffraction (HRXRD) revealed the epitaxial nature of the films, with a full width at half-maximum (FWHM) of approximately 0.08 degrees for the film (compared to 0.005 degrees for the substrate) and the presence of optical fringes on both sides of the LuIG (444) peak, indicating high film quality. Magnetization measurements revealed antiferromagnetic ordering in the films. A comprehensive study of the thickness-dependent magnetic properties of LuIG films and spin pumping phenomena in LuIG/Pt heterostructures will also be presented.