Zhang Z H, Wang Xuefeng, Xu J B, Muller S, Ronning C, Li Quan
Department of Physics, The Chinese University of Hong Kong, Shatin, New Territory, Hong Kong SAR, China.
Nat Nanotechnol. 2009 Aug;4(8):523-7. doi: 10.1038/nnano.2009.181. Epub 2009 Jul 13.
Semiconductors doped with magnetic ions, also known as dilute magnetic semiconductors, are both semiconducting and ferromagnetic. It remains unclear, however, whether this ferromagnetism is intrinsic, as is required for spintronic applications, or is due instead to dopant clustering. Here, we report conclusive evidence for intrinsic ferromagnetism in individual ZnO nanoparticles doped with transition metal ions. Through a simultaneous magnetic and microstructural characterization using electron magnetic chiral dichroism and channelling-enhanced electron energy loss microanalysis, respectively, we show that ZnO nanoparticles have intrinsic ferromagnetism when doped with cobalt, but not when doped with iron.
掺杂磁性离子的半导体，也称为稀磁半导体，兼具半导体性和铁磁性。然而，这种铁磁性是自旋电子学应用所要求的本征特性，还是由掺杂剂聚集导致的，目前仍不清楚。在此，我们报告了掺杂过渡金属离子的单个ZnO纳米颗粒中存在本征铁磁性的确凿证据。通过分别使用电子磁圆二色性和沟道增强电子能量损失微分析对磁性和微观结构进行同步表征，我们发现，ZnO纳米颗粒在掺杂钴时具有本征铁磁性，而掺杂铁时则没有。
