Room temperature ferromagnetism of Co-doped TiO2 nanotube arrays prepared by sol-gel template synthesis

In this Letter, we report a sol-gel template method to prepare Co-doped TiO2 nanotubes arrays with room temperature ferromagnetism (RTFM). The results support that RTFM of sample is related to the oxygen vacancies created by the Co2+ substitution of Ti4+ site in TiO2, not being caused by Co metal.