Dielectric properties of valence compensated Ca1-xBixTi1-xCrxO3 perovskite prepared using the sol-gel process

Abstract Ca 1− x Bi x Nb 1− x Cr x O 3 ( x =0.01–0.5) ceramic powders were synthesized using the sol–gel process. The single-phase solids can be presented at x =0.01 and 0.03. The coexistence of orthorhombic perovskite and the secondary phase of BiCrO 3 was verified, as presented for x= 0.05–0.5. Grains with a micro-cube topography were obtained for x =0.3–0.5. The average grain size is about 0.4 and 1.1 μm for x =0.3 and 0.5, respectively. The highest dielectric constant peak was measured at around 55 °C for x =0.5 and at 75 °C for x =0.3. The high dielectric constant was caused by the formation of barrier layers at the interface of the bi-phase mixed ceramics. Space charge polarization contributed to the observed behavior.

[1]  Liang-ying Zhang,et al.  Dielectric properties and microstructure of magnesium-doped Ba1+k(Ti1-xCax)O3-x+k ceramics , 2004 .

[2]  R. Freer,et al.  Structural study of Ca0.7Nd0.3Ti0.7Al0.3O3 dielectric ceramics using synchrotron X-ray diffraction , 2003 .

[3]  J. Brebner,et al.  Optical absorption and transport in semiconducting SrTiO 3 , 1975 .

[4]  S. Neirman,et al.  Dielectric properties of donor-doped polycrystalline SrTiO3 , 1982 .

[5]  S. Singh,et al.  Crystallographic phases, phase transitions, and barrier layer formation in (1 − x) [Pb(Fe_1/2Nb_1/2)O_3]−xPbTiO_3 , 2003 .

[6]  Electrical conduction and dielectric behavior of the Gd1−xCaxCoO3 system synthesized by the chemical route (x=0.10, 0.20, 0.30) , 2003 .

[7]  Hans Schmid,et al.  Multi-ferroic magnetoelectrics , 1994 .

[8]  P. Vilarinho,et al.  Solubility of bismuth oxide in barium titanate , 1999 .

[9]  C. Daul,et al.  First Principles Search for Multiferroism in BiCrO3 , 2002 .

[10]  J. Bass,et al.  Orthorhombic perovskite CaTiO3 and CdTiO3: structure and space group , 1987 .

[11]  O. Parkash,et al.  Synthesis, structure and electrical conduction behaviour of the Ca1 − xLaxSn1 − xCo1 − xO3 system , 1995 .

[12]  J. Hauck,et al.  Structure families of ZrO2- and CaTiO3-related ionic conductors , 2000 .

[13]  F. Morrison,et al.  CaCu3Ti4O12: One-step internal barrier layer capacitor , 2002 .

[14]  U. Guth,et al.  Synthesis, crystal structure, oxygen stoichiometry, and electrical conductivity of La1−aCaaCr0.2Ti0.8O3−δ , 2003 .

[15]  D. Banerjee,et al.  Oxidation of aqueous Cr(III) at birnessite surfaces: constraints on reaction mechanism , 1999 .

[16]  M. Subramanian,et al.  Noval tunable ferroelectric compositions: Ba1−xLnxTi1−xMxO3 (Ln=La, Sm, Gd, Dy. M=Al, Fe, Cr) , 2000 .

[17]  M. Barroso,et al.  Preparation and characterization of CuZnAl catalysts by citrate gel process , 2006 .

[18]  R. Newnham,et al.  Dielectric and Ferroelectric Properties of Ceramics in the Pb(Zn 1/3Nb2/3)O3‐BaTiO3‐PbTiO3 System , 1987 .

[19]  A. Nowick,et al.  Dielectric relaxation of paired defects in perovskite-type oxides , 1994 .

[20]  A. Molak,et al.  XPS examination of newly obtained (Na0.5Pb0.5)(Mn0.5Nb0.5)O3 ceramics , 2005 .

[21]  T. Fang,et al.  Structure and dielectric relaxation properties of Na1−xLaxNb1−xCrxO3 perovskites , 2006 .

[22]  R. Moos,et al.  Defect Chemistry of Donor‐Doped and Undoped Strontium Titanate Ceramics between 1000° and 1400°C , 2005 .