• • Annealed CuCrSe2 (A-CuCrSe2) nanosheets exhibit robust ferromagnetic ordering above 300 K, a significant increase from the pristine Tc of ~120 K, enabling room-temperature spintronic operation.
• • The Se vacancy concentration is approximately 10%, as confirmed by structural and compositional analyses, which is critical for tuning magnetic properties without altering the layered crystal structure.
• • Anomalous Hall effect (AHE) measurements reveal the coexistence of two ferromagnetic phases within the same sample, with Tc values of ~120 K and >300 K, indicating spatially heterogeneous magnetic ordering that could be exploited for multi-state memory devices.
• • Density functional theory (DFT) calculations provide mechanistic insight, showing that Se vacancies modulate magnetic exchange interactions, offering a design principle for achieving high-Tc 2D magnets through anion engineering.