Ferromagnetic spin-order in SnO2 nanoparticles with nonmagnetic Li doping

Abstract

Li-doped SnO2 nanoparticles were synthesized via the sol–gel method in this work. The structural analysis and optical properties analysis reveal that most Li atoms are incorporated at Sn lattice sites which red-shift the band-gap due to the formation of impurity band below 6 at% Li doping. With further doping, extra Li atoms will occupy at interstitial sites. The substitution doping of Li can enhance the ferromagnetism, and the largest saturation magnetization was found in Sn0.94Li0.06O2 nanoparticles. The origin of the ferromagnetism is attributed to the trapped holes in O 2p orbital. On the other hand, Li interstitials introduce electrons in the lattice, which can combine with the holes and suppress the magnetic moment forming, leading to the reduction of the ferromagnetism.