Magnetic properties of ZnO nanopowders

作者：Xu Qingyu^*; Zhou Shengqiang; Schmidt Heidemarie

来源：Journal of Alloys and Compounds, 2009, 487(1-2): 665-667.

DOI：10.1016/j.jallcom.2009.08.033

• Diluted magnetic semiconductor
• ZnO
• Magnetism
• Defect

We report the magnetic characterization of ZnO nanopowders with an average grain size of about 50 nm prepared by sol-gel method. At room temperature, ZnO nanopowders exhibit diamagnetism like bulk ZnO. However, strong paramagnetism was observed at 4 K. With increasing temperature, ferromagnetic to paramagnetic transition happens at around 90 K. Paramagnetism changes to diamagnetism at around 100 K, which is due to the competition between the paramagnetism from defects and diamagnetism from the bulk ZnO. Our work clearly demonstrates that the interaction between the defects is short-range. Thus the interaction between the defects is weak due to low defect concentration. It is suggested that a high defect concentration is needed for room temperature ferromagnetism.

• 出版日期2009-11-13
• 单位东南大学