GROWTH, OPTICAL AND MAGNETIC PROPERTIES OF Co-DOPED TiO2 CRYSTAL

Abstract

Co -doped TiO2 crystals (Co:TiO2) were grown by Czochralski growth (CZ) method and the edge-defined film-fed growth (EFG) method, respectively. Therein, EFG was an effective method to grow a higher quality Co:TiO2 crystal without the reverse flow of the melt. This as-grown crystal reaches a larger dimension of 10 mm × 15 mm × 18mm. XRD analysis confirms that as-grown crystal is isostructural with TiO2 rutile phase. Moreover, this crystal has ferromagnetism at room temperature and the magnetic moment of Co ion is 1.25 × 10-2 μB/Co . After annealed at 1273 K, Co:TiO2 crystal enhances obviously its optical transmittance, while this crystal shows diamagnetism due to the disappearance of the ferromagnetic signal.