Compensation-Like Temperature and Spin-Flip Switch in Strained Thulium Iron Garnet Thin Films: Tuning Sublattice Interactions for Ferrimagnetic Spintronics
来源：ACS Publications
Certain rare-earth iron garnet (RIG) thin films combine desirable properties such as low magnetic damping, high magnetostriction, and, in some cases, perpendicular magnetic anisotropy (PMA), making them attractive for spintronics applications. However, the interplay between their magnetic sublattices in confined films remains poorly explored, particularly the coupling between 3d and 4f electrons. Here, we investigate the magnetic properties of a 30 nm-thick thulium iron garnet (TmIG) thin film, where tensile strain promotes PMA. SQUID magnetometry and X-ray magnetic circular dichroism measurements reveal a magnetization minimum near 50 K under moderate magnetic fields, leading to a compensation-like temperature (Tcomp-like), a feature absent in bulk TmIG. The presence of Tcomp-like is particularly relevant for controlling magnetization dynamics through compensation phenomena. Additionally, we observe a field-induced spin-flip transition in the Tm sublattice, where Tm moments reorient and align ferromagnetically with respect to the Fe sublattices. This mechanism can be exploited for energy-efficient magnetization reversal. These findings provide insights into strain-driven magnetic phenomena in rare-earth iron garnet thin films, highlighting the interplay between exchange interactions and anisotropy in confined geometries, which is crucial for the development of spintronic and magnonic devices.
In this study, we investigated the magnetic properties of a 30 nm-thick TmIG thin film over a (111) oriented GGG substrate annealed at 900 °C, a condition that induces tensile strain, creating a stable PMA. (11) The SQUID magnetometry and element-specific X-ray magnetic circular dichroism (XMCD) measurements revealed a distinct compensation-like temperature (Tcomp-like) near 50 K under moderate magnetic fields, absent in bulk TmIG, which we attribute to modifications in exchange interactions and sublattice anisotropies. Additionally, we observed a field-induced spin-flip of the Tm sublattice, a phenomenon not observed for the Fe sublattices, highlighting the distinct response of the rare-earth and transition-metal sublattices to external fields. This study advances both the fundamental understanding of TmIG thin films and their technological potential for future spintronic and magnonic applications.