Indium vacancy induced d0 ferromagnetism in Li-doped In2O3 nanoparticles

Li-doped In2O3 nanoparticles with room temperature d(0) ferromagnetism were prepared by a sol-gel method. X-ray diffraction, X-ray photoelectron spectroscopy and photoluminescence were carried out to investigate the effects of Li incorporation on the lattice defects. As the content of Li increases, nonmonotonic changes in shifts of XRD peak (2 2 2) and the intensity ratios of indium vacancies related photoluminescence peak (PII) with respect to oxygen vacancies related peak (P-I) are observed. Results show that at low doping level (<= 2 at.%) Li prefers to occupy In sites, while with further doping the interstitial sites are more favorable for Li. Combined with the consistent non-monotonic change in saturation magnetization, we think that indium vacancies resulting from Li-doping play an important role in inducing d(0) ferromagnetism in our Li-doped In2O3 nanoparticles, and the FM coupling is mainly mediated by the Li-In-O-NN-V-In-O-NN-Li-In chains. (C) 2017 Elsevier B.V. All rights reserved.