Gilbert damping of NiFe thin films grown on two-dimensional chiral hybrid lead-iodide perovskites

The phenomenon of chirality-induced spin selectivity (CISS) refers to the coupling between structural chirality and the spin polarization of conduction electrons. While previous studies of CISS have primarily focused on systems exhibiting charge current flow, our investigation aims to explore CISS within a charge-current-free environment. This approach is intended to overcome the challenges posed by pinholes in chiral molecular films. In this study, we investigated the Gilbert damping of NiFe layers deposited on two-dimensional chiral hybrid lead-iodide perovskites, utilizing the time-resolved magneto-optical Kerr effect. Our results reveal a minor variation in the Gilbert damping constant on the magnetization direction of the NiFe. This subtle change in the damping constant, observed when pure spin current is injected from NiFe to the chiral perovskite via spin pumping, aligns with previous observations of modest CISS-induced magnetoresistance in a multilayer device, contrasting with the significant magnetoresistance detected in spin-polarized conductive atomic force microscopy measurements. Our findings contribute valuable insight into the understandings of CISS-related phenomena, paving the way for further research in this field.