Alloys of CoI2 Nanoclusters Embedded in the PbI2 Lattice Exhibiting High-Temperature Hysteretic Paramagnetic Transitions and Low-Temperature Diverse Magnetic Short-Range Ordering.

Dilute magnetic semiconductors (DMSs) are crucial for various spintronic and magneto-optical applications, typically created by doping d- or f-orbital-based metal ions into wide bandgap nonmagnetic semiconductors. In this study, we synthesized Pb_1–xCo_xI₂ (x = 0.05–0.14) alloys by doping PbI₂ with Co²⁺ ions using a simple mechanochemical method and characterized their morphology, structure, thermal stability, and magnetic properties. The Co²⁺ ions in the alloys formed CoI₂ clusters with dimensions less than 10 nm, homogeneously distributed within the PbI₂ lattice. These alloys exhibited a paramagnetic phase transition with a thermal hysteresis loop at high temperatures (>370 K) and Co²⁺-content-dependent magnetic short-range ordering behaviors (spin glass, cluster glass, or superparamagnetism) at low temperatures (<15 K). The strong interactions between itinerant electrons and the localized 3d electrons of Co²⁺ ions indicate Pb_1–xCo_xI₂ alloys, with characteristic behaviors observed in DMSs. This study demonstrates that mechanochemical synthesis is a facile and efficient method for preparing alloys of van der Waals crystals, offering precise control over alloy composition, particularly when dealing with reaction systems involving components with different soft–hard acid–base properties. [ABSTRACT FROM AUTHOR]