Tunable magnetic properties of SiC obtained by microwave heating

•Pure-phase SiC particles can be synthesized by a low-cost and simple method.•The as-obtained SiC exhibit ferromagnetism around room temperature.•The magnetic properties of SiC can be reduced and enhanced by post-treatment.•The ferromagnetism is attributed to the coexistence of interface and point defects.

To improve the magnetic properties of SiC-based semiconductor without any metal impurity, Si, SiOx and graphite powders were used as raw materials and heated to 1400 °C under microwave irradiation. Ball-milling pre-treatment was employed to obtain high growth rate of SiC. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to analyze the crystal structure and morphology of the as-obtained SiC products. The results show that the products are mainly composed of 3C-SiC particles. The vibrating sample magnetometer (VSM) analysis revealed that the SiC products can exhibit ferromagnetism around room temperature with saturated magnetization of 0.9 emu/g. Corrosion treatment and coating with oxide were also performed to further study the origin of the ferromagnetism of the SiC-based materials. It is found that the saturated magnetization can be clearly reduced by corrosion treatment and reinforced by coating post-treatment without any transition-metal dopants or ion-implantation.