Study on magnetism, swelling and their correlation of SiC ceramics under nickel ion irradiation

Abstract The main defects in 3C–silicon carbide (3C–SiC), including carbon vacancies (V C ), silicon vacancies (V Si ), carbon–silicon divacancies (V C –V Si ), and nickel atoms at substitutional (Ni Si ) and interstitial (Ni I ) sites, were controlled through 1 MeV Ni⁺ irradiation. This approach effectively distinguishes the effects of magnetic atoms and defects on the magnetic properties of 3C–SiC. Experimental and theoretical results reveal that the primary source of magnetism is not the dopant Ni atoms but rather V C –V Si ‐induced ferromagnetism, driven by strong Ruderman–Kittel–Kasuya–Yosida (RKKY) exchange interactions. This magnetism is closely linked to irradiation swelling, which affects the distances between V C –V Si . As irradiation swelling increases, the distance between V C –V Si grows, causing their magnetic interaction to transition from ferromagnetic to antiferromagnetic and eventually vanish. These findings demonstrate that adjusting irradiation parameters can effectively modulate the magnetism of SiC by controlling defect formation and swelling behavior.