The Impact of Hydrogenation Conditions on the Physical Properties of the Degenerated Ni/Al Co-doped Diluted Magnetic Semiconductor Anatase Nanoparticles

Anatase (TiO2) nanoparticles co-doped with Ni/Al ions were synthesized by a thermoprecipitation method. The samples were characterized by using XRay diffraction and optical absorption spectroscopy. The structural/optical investigations established the development of substitutional solid solutions: TiO2:Ni:Al. The magnetization investigations were performed to study the generated stable ferromagnetic properties of the samples due to the Ni²⁺ doping. To boost the created ferromagnetic properties, Al ions co-dopings were employed to supply/densify the itinerant electrons. It was planned to decide on the suitable hydrogenation conditions and temperature (TH), which are necessary to create appreciable strength of ferromagnetic properties in the host co-doped samples based on TiO2 for practical uses. The results established that the ferromagnetic energy (Umag) was increased by ~240% and the saturation magnetization by ~140% with increasing of TH from 400 °C to 500°C. The obtained Msat was higher by ~50 times than that previously attained for Ni-doped TiO2. Such novel results were discussed and explained through the spin-spin Heisenberg interactions.