Defects-Induced Room Temperature Ferromagnetism in ZnO Nanorods Grown from ε-Zn(OH)2

摘要

This paper reports the zinc interstitial-induced room temperature ferromagnetism (RT-FM) in undoped ZnO nanorods synthesized by aging ε-Zn(OH)2 precursor in 0-2 mol·L~(-1) NaOH at 80 °C for 10.0 h. The variations of the defect states and ferromagnetism of the ZnO nanorods with NaOH concentration were investigated by X-ray diffraction, Raman scattering, photoluminescence, electron spin resonance, X-ray photoelectron spectroscopy, and superconducting quantum interference device so as to identify the origin of RT-FM. The experimental results revealed that the increase of the NaOH concentration led to the increase of the oxygen-related defects but the decrease of the zinc intcrstitials in association with the magnetization value. A direct correlation between the ferromagnetism and the relative concentration of the zinc intcrstitials was established, which indicated that the zinc interstitials may play an important role in mediating the RT-FM in the undoped ZnO nanorods.