Microstructure study of the Co-added FePt thin films with high energy density

✍ Scribed by Yuan, F. T. ;Hsiao, H. N. ;Chen, S. K. ;Chang, H. W. ;You, K. L. ;Yao, Y. D.

• Book ID: 105364743
• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 491 KB
• Volume: 204
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200777392

✦ Synopsis

Abstract

Microstructure, crystal structure, and magnetic properties of the Fe~49–x~Co~x~Pt~51~ (x = 0, 0.7, 1.3, 2.2) thin films deposited on glass substrates were investigated. The addition of Co was found to enhance the magnetization of the FePt L l~0~ phase, thus increases the energy product, (BH)~max~. A maximum value of (BH)~max~ of 18.4 MGOe was obtained in the sample with x = 1.3 annealing at 500 °C. The microstructure results indicated that significant grain refining was found in the x = 2.2 sample, which reduced from averagely 60 nm for the x = 0.0∼1.3 sample to 30 nm. The concentration of Co was uniform in the Fe‐Pt‐Co film except x = 1.3 film, in which small grains with 10∼20 nm in diameter showed higher percentage of Co. Corresponding to the compositional inhomogeneity, X‐ray structural analysis revealed that the x = 1.3 film contained about 20 vol.% disordered fcc phase, which was much higher than the other composition samples (<7 vol.%). The exchanging coupling between the ordered and disordered phase can explain the enhanced magnetic properties. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)