GX and GCW drafted the manuscript. JYH

prepared the CNT film and metal deposition. GCW and CY carried out the fabrication of LED devices. GX conducted the experiment design and analysis of all the experiments. LQQ and FSS participated in all the discussion on this study. All authors read and approved the final manuscript.”
“Background The complex mechanisms that allow ferromagnetic order at room temperature in diluted magnetic oxides (DMO) are a controversial subject as magnetic behavior is strongly dependent on the synthesis method and it is very difficult to obtain reproducible homogeneity on samples. It has been widely supported that BIBW2992 manufacturer ferromagnetism is originated by structural defects [1, 2], mainly oxygen vacancies [3], but there exist some other structural defects such as interstitial cations [1, 4], cation vacancies [5],

impurities [6], and if we consider so, the common doping with 3d ions [7]. It has been shown theoretically and experimentally ([8] and references there in, [9]) that almost all of these defects have magnetic moment. On the other hand, some other systems report the absence of room temperature ferromagnetism on the same material combination. Coey et al. reported the construction of a phase diagram [10] for DMO, including percolation thresholds for oxygen vacancies (VO) and doping cations. Depending on the combination of these important defects, AZD5363 cell line ferromagnetic, paramagnetic, or antiferromagnetic order can be presented on semiconducting or insulating oxides. Structural disorder can also be present in epitaxial thin films where crystalline order does not mean absence of Schottky and Frenkel defects. Epitaxial films are normally grown under thermodynamic equilibrium, avoiding an excessive formation Ponatinib in vivo of punctual defects higher than that intrinsically found: interstitial cations or VO in ZnO, TiO2, or SnO2. The most popular mechanism for ferromagnetic order in DMO is the bound magnetic polaron (BMP) where a trapped electron at the site of the VO, with a hydrogenic radius (0.4 to 0.6 nm), intercepts and polarizes the magnetic moment from 3d

ions creating ferromagnetic order. Percolation of such BMPs creates a spin-polarized impurity band. The polarization of this band depends on the energetic overlapping with the spin split 3d bands of the cation. This is a reason which holds that no ferromagnetism would be expected for certain systems such as SnO2: Sc, Ti, and Zn [3] or ZnO: Cr [11]. On the other hand, ferromagnetism evidence on SnO2:Zn nanorods [12] was recently reported. It was proposed that substitutional Zn induced the formation of Sni defects to which is attributed the magnetic moment. This model is reinforced by theoretical calculations carried out by several groups [13, 14]. The model used to refer the origin of magnetism based on interstitial cations is named BMP’ [15].