The study reports the observation of room temperature ferromagnetism in transparent anatase TiO2 thin films doped with cobalt (Co) at concentrations ranging from 0 to 8%. Using a combinatorial screening approach, the researchers fabricated a library of Ti1-xCoxO2 films on LaAlO3 and SrTiO3 substrates. X-ray diffraction and transmission electron microscopy confirmed the homogeneous distribution of Co up to x=0.08, with no signs of impurity segregation. Magnetic microscopy images revealed magnetic domain structures in the films, indicating long-range ferromagnetic ordering. The films exhibited a spontaneous magnetic moment of 0.32 Bohr magnetons per Co atom and remained ferromagnetic above room temperature. Additionally, the films showed a positive magnetoresistance of up to 60% at 2K. The optical properties of the films were excellent, maintaining transparency in the visible and near-infrared regions, and the films exhibited a band gap at 400nm. The findings suggest that the ferromagnetism is due to the local spins of Co ions, and the underlying microscopic mechanism of long-range order remains a topic of further investigation.The study reports the observation of room temperature ferromagnetism in transparent anatase TiO2 thin films doped with cobalt (Co) at concentrations ranging from 0 to 8%. Using a combinatorial screening approach, the researchers fabricated a library of Ti1-xCoxO2 films on LaAlO3 and SrTiO3 substrates. X-ray diffraction and transmission electron microscopy confirmed the homogeneous distribution of Co up to x=0.08, with no signs of impurity segregation. Magnetic microscopy images revealed magnetic domain structures in the films, indicating long-range ferromagnetic ordering. The films exhibited a spontaneous magnetic moment of 0.32 Bohr magnetons per Co atom and remained ferromagnetic above room temperature. Additionally, the films showed a positive magnetoresistance of up to 60% at 2K. The optical properties of the films were excellent, maintaining transparency in the visible and near-infrared regions, and the films exhibited a band gap at 400nm. The findings suggest that the ferromagnetism is due to the local spins of Co ions, and the underlying microscopic mechanism of long-range order remains a topic of further investigation.