Room Temperature Ferromagnetic Ordering from Bound Magnetic Polarons in Rare Earth Doped Ultrathin MoS2 Nanosheets

Abstract

Dilute magnetic semiconductors (DMS) imbued with room temperature ferromagnetic capabilities that arise from bound magnetic polarons (BMPs) have been attractive for spintronics, information storage and magneto-optical applications. In particular, the inclusion of rare-earth lanthanide ions as magnetic dopants in semiconductors presents significant potential owing to their strong free ion magnetic moments. Here, we evaluate the influence of various rare earth dopants (Tb, Er, Eu) magnetically coupled to vacancy carrier spins in MoS2 nanosheets. The manifested ferromagnetic magnitudes adopt a trend that differs from that of the free ion moments, with 5% Tb-doped MoS2 presenting a maximum saturation magnetization. The characteristic dependence of sample magnetization upon dopant concentration and annealing stringency (defect concentration) justifies the BMP model in describing the system. The rational creation of these ferromagnetic nanosheets is expected to provide value in low temperature, solution-based processing of spintronic components into monolithic integrated electronics and multifunctional devices. These findings are also expected to shape extensive understanding towards the design of rare earth doped transition metal dichalcogenides (TMDs) as DMS for such future spintronic applications.