Bulletin of the Korean Chemical Society

Korean Chemical Society (대한화학회)
권호 표지
DOI QR코드

DOI QR Code

Study of Nonstoichiometry and Physical Properties of the $Ca_xEu_{1-x}FeO_{3-y}$ System

  • Published : 1994.07.20
Download PDF
⟨ Previous Next ⟩

Abstract

A series of samples of the ${Ca_xEu_{1-x}FeO_{3-y}$ (x=0.00, 0.25, 0.50, 0.75, and 1.00) system has been prepared at $1,250^{\circ}C$ under an atmospheric air pressure. X-ray diffraction analysis of the solid solution assigns the structure of the compositions of x=0.00, 0.25, 0.50, and 0.75 to the orthoferrite-type orthorhombic system, and that of x=1.00 to the brownmillerite-type orthorhombic one. The mole ratios of $Fe^{4+}$ ion in the solid solutions or ${\tau}$ values were determined by the Mohr's salt analysis and nonstoichiometric chemical formulas of the system were formulated from x, ${\tau}$, and y values. From the result of the Mossbauer spectroscopy, the coordination and magnetic property of the iron ion are discussed. The electrical conductivities are measured as a function of temperature. The activation energy is minimum at the composition of x=0.25. The conduction mechanism can be explained by the hopping of electrons between the mixed valences of $Fe^{3+}\;and\;Fe^{4+}$ ions.

Keywords

References

  1. J. Solid State Chem. v.73 Yo, C. H.;Lee, E. S.;Pyun, M. S.
  2. J. Kor. Chem. Soc. v.35 no.3 Yo. C. H.;Roh, K. S.;Lee, S. J.;Kim, K. H.;Oh, E. J.
  3. J. Solid State Chem. v.105 Ryu, K. H.;Roh, K. S.;Lee, S. J.;Yo, C. H.
  4. J. Solid State Chem. v.73 Rodriguez, J.;Fontcuberta, J.;Longworth, G.;Vallet-Regi M.;Gonzalez-Calbet, J. M.
  5. J. Solid State Chem. v.50 Buffat, B.;Demazeau, G.;Pouchard, M.;Dance, J. M.;Hagenmuller, P.
  6. J. Solid State Chem. v.74 Parras, M.;Vallet-Regi M.;Gonzalez-Calbet, J. M.;Allarrio-Franco, M.;Grenier, J. C.
  7. J. Electrochem. Soc. v.134 no.7 Wattiaux, A.;Grenier, J. C.;Pouchard, M.;Hagenmuller, P.
  8. thesis, Ph. D Lee, S. J.
  9. J. Solid State Chem. v.39 Takano, M.;Kawachi, J.;Nakanishi, J.;Takeda, Y.
  10. J. Appl. Phys. v.39 Racah, P. M.;Goodenough, J. B.
  11. J. Solid State Chem. v.93 Roosmalen, J. A. M. V.;Cordfunke, E. H. P.
  12. Mat. Res. Bll. v.17 Grenier, J. C.;Fournes, L.;Pouchard, M.;Hagenmuller, P.
  13. J. Mat. Chem. v.2 no.1 Gibb, T. C.;Battle, P. D.;Bollen, S. K.;Whitehead, R. J.
  14. J. Chem. Soc. Dalton Trans. Gibb, T. C.
  15. J. Solid State Chem. v.88 Matsuo M.;Gibb, T. C.
  16. J. Solid State Chem. v.73 Takano, M.;Olita, T.;Nakayama, N.;Bando, Y.;Takeda, Y.;Tamamoto, O.;Goodenough, J. B.
  17. Phys. Rev. v.156 no.2 Eibschutz, M.;Shtrikman, S.;Takeda, Y.
  18. J. Electrochem. Soc. v.126 Burren, P. R. V.;Dewit, J. H. W.