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KMID : 1059519880320010009
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Journal of the Korean Chemical Society
1988 Volume.32 No. 1 p.9 ~ p.14
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Nonstoichiometric Studies of the Mixed Valency La1-xCaxFeO3-y
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Yo Chul-Hyun
Pyon Woong-Bum
Lee Eun-Seok
Lee Sung-Joo
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Abstract
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Perovskite type compounds of the La1-xCaxFeO3-y system were prepared from stoichiometric mixtures of La2O3, CaCO3, and Fe(NO3)3·9H2O by heating at 1100℃ for 24 hours. The crystallographic structures of the solid solutions of all compositions were orthorhombic systems. X-ray diffraction and Mohr salt analysis revealed that at higher y value the phase transition due to vacancy ordering occured and that the lattice volume decreased when the x value was increased. The value of nonstoichiometric ratio y were found to be in the range of 0.0∼0.5. Electrical conductivities of this systems are measured in temperature range of -100 to 100℃. Ionic contribution to total conductivity was found from activation energy in the phase containing the open pathway due to vacancy ordering.
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KEYWORD
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