State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing, People's Republic of China.
J Phys Condens Matter. 2010 Jan 13;22(1):016002. doi: 10.1088/0953-8984/22/1/016002. Epub 2009 Dec 2.
Room temperature ferromagnetic Cu-doped ZnO nanowires have been synthesized using the chemical vapor deposition method. By combining structural characterizations and comparative annealing experiments, it has been found that both extrinsic (CuO nanoparticles) and intrinsic (Zn(1-x)Cu(x)O nanowires) sources are responsible for the observed ferromagnetic ordering of the as-grown samples. As regards the former, annealing in Zn vapor led to a dramatic decrease of the ferromagnetism. For the latter, a reversible switching of the ferromagnetism was observed with sequential annealings in Zn vapor and oxygen ambience respectively, which agreed well with previous reports for Cu-doped ZnO films. In addition, we have for the first time observed low temperature photoluminescence changed with magnetic properties upon annealing in different conditions, which revealed the crucial role played by interstitial zinc in directly mediating high T(c) ferromagnetism and indirectly modulating the Cu-related structured green emission via different charge transfer transitions.
室温铁磁性掺铜 ZnO 纳米线通过化学气相沉积法合成。通过结构表征和对比退火实验，发现外源性（CuO 纳米颗粒）和内源性（Zn(1-x)Cu(x)O 纳米线）来源都对所生长样品的观察到的铁磁有序负责。就前者而言，在 Zn 蒸汽中退火导致铁磁性急剧下降。对于后者，在 Zn 蒸汽和氧气环境中分别进行顺序退火时，观察到铁磁性的可逆开关，这与先前关于掺铜 ZnO 薄膜的报道一致。此外，我们首次观察到在不同条件下退火时低温光致发光随磁性的变化，这揭示了间隙锌在直接介导高 T(c)铁磁性以及通过不同电荷转移跃迁间接调制 Cu 相关结构绿光发射方面所起的关键作用。
