Micro-Raman and XPS studies of pure ZnO ceramics

We observed that ZnO bulk ceramics prepared by solid state reaction route at 1300 C exhibited unexpected room temperature ferromagnetic (RTFM) property. In the absence of any magnetic impurity the cause of room temperature ferromagnetic signal in the undoped system is certainly attributed to various kinds of native defects such as oxygen vacancies (V-O) or zinc interstitials (I-zn) and their clusters created inside the bulk ceramics during heating by slow step sintering schedule (SSSS). The micro-Raman investigation and X-ray photoelectron spectroscopy studies on the ZnO sample sintered at high temperature confirm the presence of such lattice defects. (C) 2010 Elsevier B.V. All rights reserved.