Effect of air annealing on the structure, dielectric and magnetic properties of (Co, Ni) co-doped SnO_2 nanoparticles

摘要

After our discovery of room temperature ferro-magnetism in the (Co, Ni) co-doped SnO_2 nanoparticles by co-precipitation method, we successfully annealed all (Co, Ni) co-doped SnO_2 diluted magnetic nanoparticles in air at 800℃. The effect of annealing on dielectric and magnetic properties of (Co, Ni) co-doped SnO_2 diluted magnetic nanoparticles was investigated. The as-synthesized (Co, Ni) co-doped SnO_2 nanoparticles were annealed in air at 800℃ for 2 h in an electric furnace. The dielectric constant and dielectric loss values of all (Co, Ni) co-doped SnO_2 samples decrease whereas, the electrical conductivity value increased with an increase in Ni co-doped concentration. Room temperature ferromagnetic behavior was observed in (Co, Ni) co-doped SnO_2 samples. Increasing the Ni content up to 2 % leads to an increase ferromagnetic behavior and beyond that the ferromagnetic behavior decreased. A comparative study shows that (Co, Ni) co-doped SnO_2 nanoparticles annealed in air at 800℃ have an excellent dielectric, magnetic properties and higher electrical conductivity than that of the (Co, Ni) co-doped SnO_2 annealed in air at 600℃, indicating that these nanoparticles can be used for high frequency devices, ultrahigh dielectric materials and spintronics.