Ferromagnetism observed in pristineSnO2thin films

Room temperature ferromagnetism (FM) was observed in laser ablated undoped $\mathrm{Sn}{\mathrm{O}}_{2}$ thin films grown on $\mathrm{La}\mathrm{Al}{\mathrm{O}}_{3}$ substrates (the saturated magnetization is about $12\phantom{\rule{0.3em}{0ex}}\mathrm{emu}∕{\mathrm{cm}}^{3}$, as half of that of the $\mathrm{Ti}{\mathrm{O}}_{2}$ films with the same thickness). Experiments on Mn-doped $\mathrm{Sn}{\mathrm{O}}_{2}$ films show that a transition-metal doping does not play any key role in introducing FM in the system. Mn doping (even if with a small content), in fact, just degrades the structure of the $\mathrm{Sn}{\mathrm{O}}_{2}$ host and, as a consequence, reduces its magnetic moment. Both oxygen vacancies and confinement effects are assumed to be key factors in introducing magnetic ordering into $\mathrm{Sn}{\mathrm{O}}_{2}$.