Bidirectional Magnetization Switching in a Ferrimagnetic Insulator by a Monochiral Cu(II)–Leucine Complex

Recent studies have demonstrated that magnetization switching in ferromagnets can be achieved through adsorbing chiral molecules on the surface without the need for current or external magnetic fields, offering a low-power mechanism for applications in spintronic devices. Molecules of opposite chirality cause opposite direction reversals of magnetization through the chiral-induced spin selectivity (CISS) mechanism. In this study, we demonstrate bidirectional magnetization switching in thin films of the ferrimagnetic insulator TmIG using a single-handed chiral molecule─a Cu coordination polymer of d-leucine. Through UV–vis circular dichroism and X-ray absorption spectroscopy, we determined that switching between different magnetic orientations is associated with interactions of the Cu molecules of d-leucine with the two distinct sublattices of the Fe ions in the TmIG, at the octahedral and tetrahedral sites. These results demonstrate that the CISS-driven magnetization switching in ferrimagnets is site-selective and energy-resolved. Our study demonstrates the unexpected versatility of the CISS mechanism for magnetization switching in ferrimagnets using single-chirality materials, thereby expanding the potential applications of chiral molecule adsorption-induced magnetization flipping.