Temperature Tuned Defect-Induced Magnetoresistance in Graphdiyne

This paper investigates the magnetoresistance (MR) characteristics of graphdiyne (GDY) under annealing temperatures ranging from [Formula: see text] to [Formula: see text]. The samples were synthesized via a modified non-transferred GDY film synthesis method and characterized using Raman spectroscopy and scanning electron microscopy (SEM) to confirm their morphology and structural integrity. Magnetotransport measurements were performed at 2[Formula: see text]K under magnetic fields up to 9[Formula: see text]T, revealing a significant transition from negative to positive MR as the annealing temperature increased. Specifically, GDY-400 shows a significantly higher MR, reaching approximately 100%, compared to both GDY-300 and GDY-500. These changes are attributed to internal defects generated during the annealing process, which induce the formation of magnetic moments and lead to pronounced shifts in MR with different annealing temperatures. Our studies not only offer a new perspective for the application of carbon materials in magnetoelectronics but also provide experimental evidence for a deeper understanding of the physical mechanisms underlying defect-induced magnetism.