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KMID : 1059519880320010003
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Journal of the Korean Chemical Society
1988 Volume.32 No. 1 p.3 ~ p.8
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A Study on Nonstoichiometry and Physical Properties of the Mixed Valency Sr1+xDy1-xFeO4-yFerrite System
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Yo Chul-Hyun
Lee Eun-Seok
Pyon Woong-Bum
Pyun Mu-Sil
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Abstract
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Nonstoichiometric solid solutions of the Sr1+xDy1-xFeO4-ysystem (x = 0. 00, 0. 25, 0. 50, 0. 75 and 1. 00) with layered K2NiF4 type structure were prepared at 1200℃ under atmospheric pressure. X-ray powder diffraction spectra show that the crystallographic phases of the samples are tetragonal within the x range. Nonstoichiometric chemical formulas have been determined by Mohr salt analysis and it shows that the amount of Fe4+ ion or τ value increases with increasing x. Electrical conductivities of the samples which were measured in the temperature range of -100∼200℃ under atmospheric air pressure are varied within the semiconductivity range of l0-8∼10-2(ohm-1·cm-1) and the activation energies are also varied from 0.02 to 0.08 eV. Mixed valency state of Fe3+and Fe4+in the sample of Sr1.00Dy1.00FeO4.04 was identified again by Mossbauer spectrum at 200K.
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