About this Journal Submit a Manuscript Table of Contents
Journal of Nanomaterials
Volume 2013 (2013), Article ID 954621, 8 pages
http://dx.doi.org/10.1155/2013/954621
Research Article

Magnetic Properties and Microstructure of FeOx/Fe/FePt and FeOx/FePt Films

Department of Materials Science and Engineering, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan

Received 9 July 2013; Revised 13 August 2013; Accepted 15 August 2013

Academic Editor: Guangyu Zhao

Copyright © 2013 Jai-Lin Tsai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The Fe(6 nm)/FePt film with perpendicular magnetization was deposited on the glass substrate. To study the oxygen diffusion effect on the coupling of Fe/FePt bilayer, the plasma oxidation with 0.5~7% oxygen flow ratio was performed during sputtered part of Fe layer and formed the FeOx(3 nm)/Fe(3 nm)/FePt trilayer. Two-step magnetic hysteresis loops were found in trilayer with oxygen flow ratio above 1%. The magnetization in FeOx and Fe/FePt layers was decoupled. The moments in FeOx layer were first reversed and followed by coupled Fe/FePt bilayer. The trilayer was annealed again at 500°C and 800°C for 3 minutes. When the FeOx(3 nm)/Fe(3 nm)/FePt trilayer was annealed at 500°C, the layers structure was changed to FeOx(6 nm)/FePt bilayer due to oxygen diffusion. The hard-magnetic FeOx(6 nm)/FePt film was coupled with single switching field. The FeOx/(disordered FePt) layer structure was observed with further annealing at 800°C and presented soft-magnetic loop. In summary, the coupling between soft-magnetic Fe, FeOx layer, and hard-magnetic L10 FePt layer can be controlled by the oxygen diffusion behavior, and the oxidation of Fe layer was tuned by the annealing temperature. The ordered L10 FePt layer was deteriorated by oxygen and became disordered FePt when the annealed temperature was up to 800°C.