A
titanium dioxide.
cobalt magnetic film is provided that is useful to make up a photocatalyst having high catalytic capability, a
semiconductor material having an optical, an electrical and a magnetic function all in combination, and a transparent
magnet. The
titanium dioxide.
cobalt magnetic film has a composition expressed by
chemical formula: Ti1-xCoxO2 where 0<x<=0.3, wherein a Ti atom at its lattice position is replaced with a Co atom, and the magnetic film is a film epitaxially grown on a
single crystal substrate. The magnetic film has either
anatase or
rutile crystalline structure, has its
band gap energy varying in a range between 3.13 eV and 3.33 eV according to the concentration of Co atoms replaced for Ti atoms at their lattice positions, is capable of retaining its
magnetization even at a temperature higher than a
room temperature, and is also transparent to a visible light. I the manufacture of the
titanium dioxide.
cobalt magnetic film, a target having TiO2 and Co mixed together at a selected
mixing ratio is prepared, placed in a
vacuum chamber provided with an
atmosphere with a selected
oxygen pressure therein, and irradiated in the
vacuum chamber with a selected
laser light under selected irradiating conditions to cause TiO2 and Co to evaporate from the target and a layer of TiO2.Co to grow in a
single crystal substrate that is heated in the
vacuum chamber.