Grain Orientation and Electrical Properties of $Sr_2Nb_2O_7$ Ceramics and Thin Films

다결정 및 박막형 $Sr_2Nb_2O_7$의 입자배향과 전기적특성

  • 손창헌 (영남대학교 대학원 전자공학과) ;
  • 전상재 (영남대학교 대학원 전자공학과) ;
  • 남효덕 (영남대학교 전기전자공학부) ;
  • 이희영 (영남대학교 금속공학 및 재료공학부)
  • Published : 1998.04.01

Abstract

Polycrystalline $Sr_2Nb_2O_7$ ceramics with very high Curie temperature were sintered using the powder derived by the chemical coprecipitation method (CCP). The phase evolution and grain-orientation of sintered samples were examined by XRD, while sintering behavior, dielectric properties and polarization were studied by SEM and ferroelectric tester. Extremely high degree of grain-orientation was observed along the (0k0) direction, which resulted in anisotropic dielectric properties of the sintered samples, with the dielectric constant values approaching those for single crystal. Thin film fabrication of $Sr_2Nb_2O_7$ in the pyroniobate family was also attempted on $SiO_2$/Si(100), Pt/$SiO_2$/Si(100), Pt/Ti/$SiO_2$/Si(100) and Pt/$ZrO_2/SiO_2/Si_2(100)$ substrates, using metalorganic decomposition (MOD) process. Neodecanoate precursor solution was prepared by mixing strontium neodecanoate with niobium neodecanoate synthesized from niobium ethoxide. It was found that $Sr_2Nb_2O_7$ single phase appeared in XRD patterns the samples annealed above $950^{\circ}C$. The effect of substrate type on film microstructure and dielectric properties was observed.

Keywords

References

  1. Phys. Rev. v.88 W. R. Cook Jr.;H. Jaffe
  2. Acta Cryst. v.B37 Compounds with Perovskite-Type Slabs. Ⅳ. Ferroelectric Phase N. Ishizawa;F. Marumo;S. Iwai
  3. J. Phys. Soc. Japan v.30 Ferroelectric properties of $Sr_{2}Nb_{2}O_{7}$ Single Crystal S. Nanamatsu;M. Kimura;K. Doi;M. Takahashi
  4. J. Am Ceram. Soc. v.75 Sol-Gel Synthesis of Strontium Pyroniobate A. V. Prasadarao;U. Selvaraj;S. Komarneni;A. S. Bhalla
  5. J. Mater. Res. v.10 no.3 Fabrication of Thin Films by Sol-Gel Processing A. V. Prasadarao;U. Selvaraj;S. Komarneni;S. Comarneni
  6. J. Mater. Res. v.10 no.3 Fabrication of Thin Fims by Sol-Gel Processing A. V. Prasadarao;U. Selvaraj;S. Komarneni;S. Comarneni
  7. J. Am. Ceram. Soc. v.52 Preparation of High-Purity Submicron Barium Titanate Powders K. S. Madiyashi;R. T. Dolloff;J. S. SmithⅡ
  8. Mat. Let. v.10 no.3 Low temperature Synthesis of Ultrafine Barium Titanate (BaTiO₃) using Organometallic Barium and Titanate Precursors H. S. Potdar;P. Singh;S. B. Deshpande;P. D. Godbole;S. K. Data
  9. J. of Korea Sensor Society v.5 no.3 Fabrication and Electrical Properties of High Tc $A_{2}B_{2}O_{7}$ Piezoelectric Ceramics Using the Powders Prepared by the Molten Salt Synthesis Method I. H. Park;T. G. Kim;H. D. Nam
  10. Inorg, Nual. Chem. v.9 Topotactical Reaction with Ferrimagnetic Oxides Having Hexagonal Crystal Structures-1 E. F. Lotgering
  11. unpublished results S.B. Desu(et al.)
  12. J. Mat. Soc. v.26 Grain Orientation and Electrical Properties of $Sr_{2}Nb_{2}O_{7}$Ceramics M. Fukuhara;C. Y. Huang;A. S. Bhalla;R. E. Newnham