Revealing Robust Room Temperature Ferromagnetism in Gd-Doped Few-Layered MoS Thin Films.

2D MoS holds great promise for spintronics, yet is limited by intrinsic diamagnetism. This study demonstrates inducing ferromagnetic behavior in MoS films doped with 0.47% Gd, achieving an ultrahigh saturation magnetization of 454 emu/cm in a few-layered film over 11-times higher than bulk films (40 nm). Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray magnetic circular dichroism, and density functional theory (DFT) calculations reveal an interplay between Gd dopants and Mo, S vacancies (V), leading to the formation of bound magnetic polarons (BMPs) that drive ferromagnetic ordering. HS annealing and DFT calculations reveal that defect healing reduces the saturation magnetization by 83%. High sulfur migration barrier in few-layered films helps preserve BMPs, thereby sustaining ferromagnetism, whereas lower migration barriers in bulk films lead to suppression. These findings highlight the synergy between Gd doping and defect engineering in achieving ultrahigh room-temperature ferromagnetism, offering a scalable strategy for developing high-performance 2D magnetic materials for spintronic applications.