Magnetic Properties of Co-Doped TiO₂ Films Grown on TiN Buffered Silicon Substrates

Co-doped TiO₂ thin films are grown on TiN buffered silicon substrates by the pulsed laser deposition method and then hydrogenated. Transmission electron microscopy and high-angle annular dark-field scanning transmission electron microscopy measurements have shown that the TiN buffer layer can suffer a 400°C deposition temperature and prevent the growth of silicon dioxide on silicon. After that, the room temperature ferromagnetism behaviors are observed in the hydrogenated samples, which are measured by the alternating gradient magnetometer. X-ray photoelectron spectroscopy and x-ray absorption fine structure measurements have revealed the existence of cobalt clusters. According to the material analysis, the magnetic behavior after hydrogenation is suggested to be induced by the enhancement of cobalt clusters.