EPR/FMR Investigation of Mn-Doped SiCN Ceramics

SiCN magnetic ceramics doped with Mn2+ ions were synthesized at the pyrolysis temperature of 1,100A degrees C, using CERASET (TM) as liquid polymer precursor and polymer manganese(II) acetylacetonate as dopant, and investigated by electron paramagnetic resonance (EPR)/ferromagnetic resonance (FMR) technique. The predominant source of ferromagnetism in SiCN samples doped with Mn ions, as synthesized here, is the ensemble of ferromagnetic nanoparticles of Mn5Si3C (x) incorporated into the amorphous SiC/Mn structure. The fluctuation of magnetization due to ferromagnetic Mn5Si3Cx particles significantly broadens the EPR lines at the phase-transition temperature (363 K). This is the first fabrication of a SiCN/Mn ceramic, which exhibits room-temperature ferromagnetism.