Defect-induced magnetism in SiC

Defect-induced magnetism describes a magnetic phenomenon in materials containing neither unpaired 3d nor 4f  electrons. Therefore, it presents a challenge to the conventional understanding of magnetism and has remained under debate for over a decade. Different from graphite and oxides which are common research venues in defect-induced magnetism, SiC is commercially available at large scale and with high quality at the microelectronic grade. Therefore, SiC presents a suitable model system for studying defect-induced ferromagnetism and exploring possible applications. Understanding and controlling defect-induced magnetism in a semiconductor like SiC opens up the possibility for producing spintronic devices based on classical semiconductor technologies. Here, we review recent studies on defect-induced magnetism in SiC. We start with a brief description about defects in SiC. Then we summarize the experimental results on defect-induced magnetism in SiC, the microscopic origin of the magnetism and the magnetic coupling mechanism. We also propose several potential applications, particularly using magnetometry as a complementary method for quantitative characterization of defects in SiC. At the end, we list the challenges from our point of view, such as controlling defects in SiC regarding their charge states, distribution and local environment, and understanding defect-induced magnetism by local and elemental selective probe techniques.