The dopant concentration and annealing temperature dependence of ferromagnetism in Co-doped ZnO thin films

✍ Scribed by Xiao-Hong Xu; Xiu-Fang Qin; Feng-Xian Jiang; Xiao-Li Li; Ya Chen; G.A. Gehring

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 533 KB
• Volume: 254
• Category: Article
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2008.01.164

✦ Synopsis

A series of Zn 1Àx Co x O thin films with the atomic fraction, x, in the range of 0.03-0.10 were deposited on glass substrates at room temperature by magnetron co-sputtering technique and subsequently coupled with the post-annealing treatment for half hour at different temperatures (350 8C and 500 8C) under vacuum. A systematic study was done on the structural, optical and magnetic properties of Zn 1Àx Co x O thin films as a function of Co concentration and annealing temperature. X-ray diffraction and UV-vis spectroscopy results indicated that there are not any secondary phases and Co 2+ substituted for Zn 2+ of ZnO host. Magnetic hysteresis loops were observed at room temperature, indicating that both the as-deposited samples and the annealed ones exhibit the room temperature ferromagnetism. It was also found that the magnetic saturation moment per Co atom decreases with increasing Co concentration, while the post-annealing treatment can enhance the magnetic moment of the films effectively.