Room temperature ferromagnetic ordering from bound magnetic polarons in rare-earth-doped ultrathin MoS2 nanosheets

Abstract

Dilute magnetic semiconductors (DMSs) endowed 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. Herein, we evaluate the influence of various rare-earth dopants (Tb³⁺, Er³⁺, and Eu³⁺) magnetically coupled to vacancy carrier spins in MoS₂ nanosheets. The manifested ferromagnetic magnitudes adopt a trend that differs from that of free ion moments, with 5% Tb-doped MoS₂ exhibiting maximum saturation magnetization. The characteristic dependence of sample magnetization on dopant concentration and stringent annealing conditions (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 contribute to a comprehensive understanding of the design of rare-earth-doped transition metal dichalcogenides (TMDs) as DMSs for such future spintronic applications.