中国物理B ›› 2011, Vol. 20 ›› Issue (7): 77701-077701.doi: 10.1088/1674-1056/20/7/077701

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Multiferroic properties of sol–gel derived Bi5Fe1-xCoxTi3O15 thin films

王伟, 武鑫华, 毛翔宇, 陈小兵   

  1. College of Physical Science and Technology, Yangzhou University, Yangzhou 225002, Chinavspace1pt
  • 收稿日期:2010-09-30 修回日期:2011-03-01 出版日期:2011-07-15 发布日期:2011-07-15
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 51072177 ) and the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province, China (Grant No. 08KJB140011).

Multiferroic properties of sol–gel derived Bi5Fe1-xCoxTi3O15 thin films

Wang Wei(王伟),Wu Xin-Hua(武鑫华),Mao Xiang-Yu(毛翔宇), and Chen Xiao-Bing(陈小兵)†   

  1. College of Physical Science and Technology, Yangzhou University, Yangzhou 225002, Chinavspace1pt
  • Received:2010-09-30 Revised:2011-03-01 Online:2011-07-15 Published:2011-07-15
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 51072177 ) and the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province, China (Grant No. 08KJB140011).

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摘要： Co-doped Bi5FeTi3O15 thin films (BFCT-x, Bi5Fe1-xCoxTi3O15) were prepared using a sol—gel technique. XRD patterns confirm their single phase Aurivillius structure, and the corresponding powder Rietveld analysis indicates the change of space group around x=0.12. The magnetic hysteresis loops are obtained and ferromagnetism is therefore confirmed in BFCT-x thin films. The remanent magnetization (Mr) first increases and reaches the maximum value of 0.42 emu/cm3 at x=0.12 due to the possible Fe3+—O—Co3+ ferromagnetic coupling. When x = 0.25, the Mr increases again because of the dominant Fe3+—O—Co3+ ferromagnetic coupling. The remanent polarization (2Pr) of BFCT-0.25 was measured to be as high as 62 μC/cm2, a 75% increase when compared with the non-doped BFCT-0 films. The 2Pr remains almost unchanged after being subjected to 5.2 × 109 read/write cycles. Greatly enhanced ferroelectric properties are considered to be associated with decreased leakage current density.

关键词: magnetism, ferroelectricity, thin film

Abstract: Co-doped Bi$_{5}$FeTi$_{3}$O$_{15}$ thin films (BFCT-$x$,  Bi$_{5}$Fe$_{1-x}$Co$_{x}$Ti$_{3}$O$_{15}$) were prepared using a sol--gel technique. XRD patterns confirm  their single phase Aurivillius structure, and the corresponding powder Rietveld analysis indicates the change  of space group around $x=0.12$. The magnetic hysteresis loops are obtained and ferromagnetism is therefore  confirmed in BFCT-$x$ thin films. The remanent magnetization ($M_{\rm r}$) first increases and reaches the  maximum value of 0.42 emu/cm$^{3}$ at $x=0.12$ due to the possible Fe$^{3+}$--O--Co$^{3+}$ ferromagnetic  coupling. When $x = 0.25$, the $M_{\rm r}$ increases again because of the dominant Fe$^{3+}$--O--Co$^{3+}$  ferromagnetic coupling. The remanent polarization ($2P_{\rm r}$) of BFCT-0.25 was measured to be as high as  62 $\mu $C/cm$^{2}$, a 75% increase when compared with the non-doped BFCT-0 films. The $2P_{\rm r}$  remains almost unchanged after being subjected to $5.2\times 10^{9}$ read/write cycles. Greatly enhanced ferroelectric properties are considered to be associated with decreased leakage current density.

Key words: magnetism, ferroelectricity, thin film

中图分类号:  (Dielectric, piezoelectric, ferroelectric, and antiferroelectric materials)

  • 77.84.-s
78.30.-j (Infrared and Raman spectra) 73.50.-h (Electronic transport phenomena in thin films)