Structure and properties of Co doped TiO2 thin films on Si(100) by a pulsed laser deposition method

Abstract

We report on the crystal structure and magnetic properties of CoxTi1-xO2 thin films (0.03 <= x <= 0.07), grown on Si(100) substrates by pulsed laser deposition (PLD) as a function of Co concentration, substrate temperature, oxygen flow rate and working pressure. The crystal structure exhibiting ferromagnetism at room temperature was found to originate from the anatase phase in the CoxTi1-xO2 thin films, which grew well on Si substrates. The saturation magnetization (M-s) was observed to increase with increasing Co concentration in the range x = 3-7%. The CoxTi1-xO2 film with x = 7% exhibits M-s = 5.31 emu/cm(3) and H-c = 92.5 Oe. The magnetic moment in the films is likely to depend upon the extent of crystallization of the anatase phase, which is related to the resistivity of the films.