Transport signatures of interfacial exchange coupling and chiral spin textures in magnetic insulator thin films*

Ferrimagnetic insulators (FMIs) attract tremendous interest for spintronic applications due to high characteristic frequency, low Gilbert damping, and absence of Ohmic loss. First, we demonstrate the critical role of dimensionality on the SOT efficiency by systematically studying the FMI layer thickness dependent SOT efficiency in tungsten/thulium iron garnet (W/TmIG) bilayers. Current-induced switching in FMI thin films is demonstrated with a thickness up to 15 nm [1]. Second, we use temperature dependent Hall measurements to identify contributions of spin Hall, magnetic proximity, and sublattice effects to the anomalous Hall signal in various heavy metal/ferrimagnetic insulator heterostructures. This approach enables detection of both the magnetic proximity effect onset temperature and magnetization compensation temperature and provides essential information regarding the interfacial exchange coupling. At last, we show the transport signatures of chiral spin textures, topological Hall effect, in the platinum/ferrimagnetic insulator bilayer. [1] Q. Shao, et al., Nat. Commun., 9, 3612 (2018)