Ferromagnetism in ZnO Nanoparticles Induced by Doping of a Nonmagnetic Element: Al

Abstract

The room-temperature ferromagnetism of Zn1−x Al x O nanoparticles synthesized by a sol−gel method is reported in this paper. X-ray diffraction and selected area electron diffraction results show that the Al atoms have successfully substituted for some of the Zn atoms in the ZnO lattice without forming other new phases. The results also show that the samples possess a typical wurtzite structure. Declaration of ferromagnetism at room temperature has been established with the observed hysteresis and the coercive field in hysteresis loops. Magnetic measurements indicate that the saturation magnetization of the samples is sensitive to the content of Al dopants and that, for Zn0.97Al0.03O, the saturation magnetization reaches the maximum of 0.012 emu/g. Combining with the results of Raman, photoluminescence, and X-ray photoelectron spectroscopies, it is suggested that the observed ferromagnetic ordering of the Zn1−x Al x O nanoparticles is related to the doping-induced oxygen vacancies.

Influence of oxygen partial pressure on the microstructural and magnetic properties of Er-doped ZnO thin films

“…12 The shoulder peak locating at 3.08 eV corresponding to V Zn emission 19 is also observed and the intensity of it decreases promptly with the increase of P O2 . Besides, two weak peaks locating at 2.85 eV (corresponding to Zn i emission) and 2.50 eV (corresponding to V o emission) [20][21][22] are also observed in EZO. And they are not obvious in other samples.…”

Modification at Lattice Scale for an Optimized Optical Response of Al<sub>x</sub>(ZnO)<sub>1-x</sub> Nanostructures

“…These Raman active modes are ascribed to the multi-phonon process (326 cm -1 ) and the E 2 2 high phonon mode (436 cm -1 ) [13][14][15]. It is evident from Raman spectra, that the variation in the intensity of the peaks is due to the incorporation of Al 3+ .…”

“…Moreover various emission characteristics and shifting of luminescence bands have been attributed to the fine nanocrystalline structures leading to a large surface area and defects [10][11][12]. Recently neat or undoped ZnO has also been investigated by incorporating light metal ions like Al 3+ for optical applications [13][14][15]. To this end, in the present study, we report the syntheses and characterization of Al doped ZnO nanostructures.…”

Zinc vacancy and erbium cluster jointly promote ferromagnetism in erbium-doped ZnO thin film

“…However, the increase in Er concentration lowers the Fermi level of ZnO, which improves the formation energy of V Zn . 20 Beside the NBE peak and the shoulder peak, two weak peaks located at 2.85 eV (corresponding to Zn i emission) and 2.50 eV (corresponding to V o emission) [21][22][23] are also observed. These two peaks alter slightly with the increase of x value.…”