%0 Journal Article
%T Influence of reducing anneal on the ferromagnetism in single crystalline Co-doped ZnO thin films<br>
%A Lu Zhong-Lin
%A Zou Wen-Qin
%A Xu Ming-Xiang
%A ZhangFeng-Ming
%A <br>
%J 中国物理 B
%D 2010
%I 
%X This paper reports that the high-quality Co-doped ZnO single crystalline films have been grown on $a$-plane sapphire substrates by using molecular-beam epitaxy. The as-grown films show high resistivity and non-ferromagnetism at room temperature, while they become good conductive and ferromagnetic after annealing in the reducing atmosphere either in the presence or absence of Zn vapour. The x-ray absorption studies indicate that all Co ions in these samples actually substituted into the ZnO lattice without formatting any detectable secondary phase. Compared with weak ferromagnetism (0.16~$\mu _{\rm B}$/Co$^{2 + })$ in the Zn$_{0.95}$Co$_{0.05}$O single crystalline film with reducing annealing in the absence of Zn vapour, the films annealed in the reducing atmosphere with Zn vapour are found to have much stronger ferromagnetism (0.65~$\mu _{\rm B}$/Co$^{2 + })$ at room temperature. This experimental studies clearly indicate that Zn interstitials are more effective than oxygen vacancies to activate the high-temperature ferromagnetism in Co-doped ZnO films, and the corresponding ferromagnetic mechanism is discussed.
%K Co-doped ZnO
%K diluted magnetic semiconductors
%K x-ray absorption fine structure
%K single crystalline thin films<br>
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=6E709DC38FA1D09A4B578DD0906875B5B44D4D294832BB8E&cid=47EA7CFDDEBB28E0&jid=CD8D6A6897B9334F09D8D1648C376FB4&aid=369C430D9B4D5E9A2AF45BD611CF07C7&yid=140ECF96957D60B2&vid=2A8D03AD8076A2E3&iid=94C357A881DFC066&journal_id=1009-1963&journal_name=中国物理&referenced_num=0&reference_num=31