Emergence of a spin Hall topological Hall effect in the noncollinear phase of the ferrimagnetic insulator terbium-iron garnet

Abstract

Magnetic compensation in rare-earth iron garnets (REIGs) offers a unique setting in which competing sublattice moments can give rise to non-collinear (canted) magnetic configurations, where the sublattice magnetizations are not aligned with each other or with the external magnetic field. We show that this compensation regime can possibly also host nontrivial magnetic textures. To explore this behavior, we investigated (111)-oriented epitaxial Tb3⁢Fe5⁢O12/Pt heterostructures across the compensation temperature region using combined transverse magneto-transport and polar Kerr microscopy. Notably, we observe a topological Hall–like signal in the vicinity of the compensation temperature, a feature often interpreted as evidence for skyrmions in the absence of direct imaging. Here, in contrast, complementary Kerr microscopy reveals instead a non-collinear multidomain state which collapses outside the compensation regime, correlating directly with the appearance and disappearance of the spin Hall topological Hall effect (SH-THE) signal. These observations cannot be accounted for by a simple multi-anomalous-Hall-effect model, ruling out common artifacts as the origin, but indicate a topologically nontrivial contribution to the Hall response. These results establish strained REIG films as a tunable platform for exploring topological responses arising from compensation-driven non-collinear ferrimagnetic phases.