Crystal structure and electric conductivity of K+-beta-ferrite with ideal composition KFe11O17

被引：30

作者：

Ito, S ^{[1
]}

Kurosawa, H ^{[1
]}

Akashi, K ^{[1
]}

Michiue, Y ^{[1
]}

Watanabe, M ^{[1
]}

机构：

[1] NATL INST RES INORGAN MAT,TSUKUBA,IBARAKI 305,JAPAN

来源：

SOLID STATE IONICS | 1996年 / 86-8卷

关键词：

crystal structures; electric conductivity; beta-alumina structure; activation energy;

D O I：

10.1016/0167-2738(96)00164-6

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Fe2+ in K1.22Fe11O17 single crystals has been oxidized by iodine to obtain an ideal composition of KFe11O17. The crystal structure was analysed based on its beta-alumina structure and a final R(F) value of 0.034 was obtained. The atom positions in the spinel block were unchanged by the oxidation. On the other hand, while the amount of K+ in BR sites was comparable to that in K1.22Fe11O17, that in the aBR sites was largely decreased. The ionic conductivity of beta-ferrite with the ideal composition was measured at 300 degrees C and found to be 3.53 . 10(-3) Omega(-1) cm(-1) in the (001) plane. The activation energy was E(a) = 0.19 eV. This ionic conductivity was twenty times lower than that of K1.22Fe11O17. The activation energy was also lowered. This is because the amount of K+ in aBR sites was relatively small. The electronic conductivity was also measured and found to be 2.05 . 10(-5) Omega(-1) cm(-1) at 300 degrees C, which is two orders of magnitude smaller than that of K1.22Fe11O17. However, the activation energy (0.45 eV) was unchanged. The hopping pairs of Fe2+ and Fe3+ would be largely decreased by the oxidation.

引用

页码：745 / 750

页数：6

共 17 条

[1]

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[2]

Boilot J. P., 1980, Solid State Ionics, V1, P69, DOI 10.1016/0167-2738(80)90023-5

[3] STUDIES OF POTASSIUM FERRITE K1+CHIFE11O17 .3. IONIC-CONDUCTIVITY AND CHEMICAL DIFFUSION [J].