Origin of room-temperature ferromagnetism in Co-doped CeO2

Co-doped CeO2 fabricated using the conventional solid-state reaction method demonstrates ferromagnetism at room temperature (RT). To investigate the origin of ferromagnetism at RT, powder X-ray diffraction analysis is first performed, in which pattern changes due to Co doping are not indicated. Subsequently, local environment analysis is carried out using X-ray absorption near-edge structure (XANES) measurements at the Co K-edge, demonstrating the metallic valence state of Co. Hence, it is confirmed that Co exists as nanosized small particles in CeO2, which demonstrates ferromagnetism at RT.