Effects of high-temperature annealing on magnetic properties of (Zn 0.91Mn 0.09)O thin films grown by RF magnetron sputtering

• Published in: Materials science & engineering. B, Solid-state materials for advanced technology Solid-state materials for advanced technology, 2006-01, Vol.126 (2), p.300-305
• Main Authors: Lee, Sejoon, Lee, H.S., Hwang, S.J., Shon, Yoon, Kang, T.W., Kim, Deuk Young, Kim, E.K.
• Format: Article
• Language: English
• Subjects: High-temperature annealing; Nano-island; Room temperature ferromagnetism; ZnMnO
• ISSN: 0921-5107; 1873-4944
• DOI: 10.1016/j.mseb.2005.12.007

The (Zn 0.91Mn 0.09)O thin film annealed at 1000 °C for 60 min in N 2 atmosphere showed two kinds of Curie temperature ( T C) values of T C1 around 130 K and T C2 above 300 K while the as-grown (Zn 0.91Mn 0.09)O thin film showed typical ferromagnetism with the T C of 108 K. It is expected that the increase of T C up to T C1 might be attributed to the enhancement of crystal magnetic anisotropy because the increases of (0 0 0 l) peak for X-ray diffraction patterns and Mn 2+-related emission for photoluminescence spectra were observed for annealed (Zn 0.91Mn 0.09)O thin films. The increase of T C above T C2 might be originated from the formation of nano-sized (Zn 0.91Mn 0.09)O islands because it was confirmed that the nano-sized (Zn 0.91Mn 0.09)O islands were formed after annealing treatment and that they revealed clearly the magnetic domains at 300 K for the measurements of atomic force microscopy and magnetic force microscopy, respectively. The room temperature ferromagnetism in the nano-sized (Zn 0.91Mn 0.09)O islands is considered to be originated from the inhomogeneous distribution of Mn ions.