Bulletin of the Korean Chemical Society

  • 제16권7호
  • /
  • Pages.600-603
  • /
  • 1995
  • /
  • 0253-2964(pISSN)
  • /
  • 1229-5949(eISSN)
대한화학회 (Korean Chemical Society)
권호 표지
DOI QR코드

DOI QR Code

Studies of Nonstoichiometry and Physical Properties of the Perovskite $Sm_{1-x}Sr_xCoO_{3-y}$ System

  • 발행 : 1995.07.20
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

A series of samples in the Sm1-xSrxCoO3-y(x=0.00, 0.25, 0.50, 0.75 and 1.00) system has been prepared at 1200 ℃ under ambient atmosphere. The X-ray diffraction patterns of the samples with x=0.00 and 0.25 are indexed with orthorhombic symmetry like GdFeO3 and x=0.50 appears to be perfectly cubic. In the tetragonal system (x=0.75), the structure is similar to that of SrCoO2.80. The composition of x=1.00, SrCoO2.52, shows the brownmillerite-type structure. The reduced lattice volume is increased with x value in this system. The chemical analysis shows the τ value (the amount of the Co4+ ions in the system) is maximized at the composition of x=0.50. Nonstoichiometric chemical formulas are determined by the x, τ and y values. The electrical conductivity has been measured in the temperature range of 78 to 1000 K. The activation energy is minimum for those of x=0.25 and x=0.50 with metallic behavior. First-order semiconductor-to-metal transition of SmCoO3 is not observed. Instead, a broad, high-order semiconductor-to-metal transition is observed. In general, the effective magnetic moment is increased with increasing τ values at low temperature. At high temperature, the magnetic moment is maximum for that of x=0.00. The 3d-electrons are collective and give ferromagnetism in x=0.50.

키워드

참고문헌

  1. J. Kor. Chem. Soc. v.35 no.3 Yo, C. H.;Rho, K. S.;Lee, S. J.;Kim, K. H.;Oh, E. J.
  2. J. Solid State Chem. v.73 Yo, C. H.;Lee, E. S.;Pyun, M. S.
  3. J. Nat. Soc. Res. Ins. v.12 Yo, C. H.;Lee, S. J.;Chang, S. H.
  4. J. Solid State Chem. v.50 Buffat, B.;Demazeau, G.;Pouchard, M.;Hagenmuller, P.
  5. J. Solid State Chem. v.41 Taguchi, H.;Shimada, M.;Koizumi, M.
  6. J. Solid State Chem. v.105 Ryu, K. H.;Lee, S. J.;Roh, K. S.;Yo, C. H.
  7. Chem. Mater. v.6 Giaguinta, D. M.Hans-Conrad zur Loye
  8. Phys. Rev. v.155 no.3 Raccah, P. M.;Goodenough, J. B.
  9. Phys. Rev. B. v.6 Bhide, V. G.;Rajoria, D. S.;Rao, C. N. R.;Rama Rao, G.
  10. Solid State Comm. v.44 no.8 Thornton, G.;Tofield, B. C.;William, D. E.
  11. Mater. Res. Bull. v.14 no.6 Grenier, J. C.;Ghodbane, S.;Demazeau, G.;Pouchard, M.;Hagenmuller, P.
  12. Mat. Res. Bull. v.21 Grenier, J. C.(et al.)
  13. Phys. Soc. Japan v.33 no.4 Takeda, T.;Watanabe, H. J.
  14. J. Appl. Phys. v.39 Raccah, P. M.;Goodenough, J. B.
  15. Phys. Rev. B. v.12 no.7 Bhide, V. G.;Rajoria, D. S.;Rao, C. N. R.;Rama Rao, G.;Jadhao, U. G.
  16. J. Phys. Chem. Solids. v.32 Casalot, A.;Dougier, P.;Hagenmuller, P.
  17. Structure and Bonding Grenier, J. C.;Pouchard, M.;Hagenmuller, P.
  18. J. Solid State Chem. v.21 Thornton, G.;Morrison, F. C.;Partington, S.;Tofield, B. C.;William, D. E.
  19. Magnetochemistry Carlin, R. L.
  20. J. Solid State Chem. v.9 Demazeau, G.;Pouchard, M.;Hagenmuller, P.