Dielectric Properties of $BaTiO_3$ System Ferroelectric Thick Films Doped with $Dy_2O_3$

$Dy_2O_3$$BaTiO_3$계 강유전체 후막의 유전특성

  • 노현지 (경상대공대 나노.신소재공학과) ;
  • 윤상은 (경상대공대 세라믹공학과) ;
  • 박상만 (경상대공대 나노.신소재공학과) ;
  • 안병립 (한양대 대학원 전기공학과) ;
  • 이성갑 (경상대 공학연구원 세라믹공학과)
  • Published : 2007.09.01

Abstract

(Ba,Sr,Ca)$TiO_3$ powders, which were prepared by sol-gel method using a solution of Ba-, Sr- and Ca-acetate and Ti iso-propoxide, were mixed with organic vehicle and the BSCT thick films were fabricated by the screen-printing techniques on high purity alumina substrates. The structural and dielectirc properties were investigated for various $Dy_2O_3$ doping contents. As a result of thermal analysis, the exothermic peak was observed at around 670^{\circ}C $ due to the formation of the polycrystalline perovskite phase. All BSCT thick films, sintered at $1420^{\circ}C$ for 2h, showed the typical XRD patterns of perovskite polycrystalline structure and no pyrochlore phase was observed. The average grain size of the specimens decreased with increasing amount of $Dy_2O_3$. The average grain size and thickness of the BSCT specimens doped with 0.1 mol% $Dy_2O_3$ were approximately $1.9{\mu}m$ and $70{\mu}m$, respectively. The relative dielectric constant decreased and dielectric loss increased with increasing amount of $Dy_2O_3$, the values of the BSCT thick films doped with 0.1 mol% $Dy_2O_3$ were 3697 and 0.4% at 1 kHz, respectively. The leakage current densities in all BSCT thick films were less than $10^{-9}A/cm^2$ at the applied electric field range of 0-20 kV/cm.

Keywords

References

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