High temperature ferromagnetism in mechanically milled 6H-SiC nanoparticles

Abstract

Silicon carbide (SiC) nanoparticles with different sizes were successfully obtained by high energy ball milling. Room temperature magnetic measurements showed that the saturation magnetization of milled-SiC nanoparticles increases monotonically from 0.0006 to 0.0032 emu/g with increasing milling time, while the bulk SiC powders present diamagnetism. Besides, the high temperature hysteresis curves indicated that the Curie temperature of the milled-SiC nanoparticles was much over 800 K. Meanwhile, the results of X-ray diffraction, Raman spectrometer and scanning electron microscope suggested that the surface defects were introduced into the milled-SiC nanoparticles. Further studies via electron spin resonance and photoluminescence proved that the surface defects are responsible for the origin of ferromagnetism in milled-SiC nanoparticles.