Effect of annealing temperature on the dielectric and magnetic response of (Co, Zn) co-doped SnO2 nanoparticles

Abstract

The effect of annealing temperature on the dielectric and magnetic properties of (Co, Zn) co-doped SnO2 nanoparticles under air/oxygen (O2) and argon (Ar) atmospheres at 600 °C have been systematically investigated. A significant decrease is observed in dielectric constant and dielectric loss resulting from the incorporation of Co and Zn into the SnO2 lattice. Higher dielectric constant and loss was observed in the O2 annealed sample. Moreover, the electrical conductivity of the (Co, Zn) co-doped SnO2 samples increased in comparison with that of pure SnO2 sample due to the increase of available charge carriers after replacement of Sn ions with Co and Zn ions. Room-temperature ferromagnetism (RTFM) was observed for both the O2 and Ar annealed (Co, Zn) co-doped SnO2 samples. However, the remanent magnetization (Mr) varied drastically for different environmental annealing processes with Mr = 0.412 and 0.20 memu/g for the O2 and Ar-annealed samples, respectively. The results show that the enhanced dielectric and magnetic properties of (Co, Zn) co-doped SnO2 sample is strongly correlated with the increase in O2 vacancies. These findings not only demonstrate that (Co, Zn) co-doped SnO2 samples show tunable RTFM, but also suggests that RTFM can be influenced by introduction of O2 vacancies during O2 annealing.