Influence of Al doping on crystal structure, magnetic and optical properties of TiO2 compound

Recently, an attempt to search for the novel material which can be applicable for spintronics devices, has become a highly debated and intensively investigated field of study. Within the scope of this investigation, Ti1-xAlxO2 (0 <= x <= 0.12) polycrystalline samples were produced using the traditional solid-state reaction method, and their crystal structure, magnetic, and optical characteristics were investigated. Single rutile phase with tetragonal crystal structure of titanium oxide is seen from the X-ray diffraction patterns study. The variation in the lattice parameter elucidate that Al3+ ions successfully substitute the Ti4+ ions. The analyses of the optical characteristics reveals that the incorporation of Al into the TiO2 matrix leads to a reduction in the optical band gap. Investigation on magnetic characteristics showed that all Ti1-xAlxO2 compounds displayed room temperature ferromagnetic nature with 81 Oe <= Hc <= 930 Oe. Hall effect measurements show that all doped samples display ptype conductivity while un-doped TiO2 exhibits n-type conductivity and with increasing Al-doping concentration, the hole carrier density rises.