High Temperature Electrical Conductivity of Perovskite La0.98Sr0.02MnO3

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J. Korean Ceram. Soc. > Volume 29(11); 1992 > Article

Journal of the Korean Ceramic Society 1992;29(11): 900.

페로프스카이트 $La_{0.98}Sr_{0.02}MnO_3$의 고온전기특성

김명철, 박순자¹

군산대학교 공과대학 재료공학과
¹서울대학교 공과대학 무기재료공학과

High Temperature Electrical Conductivity of Perovskite La0.98Sr0.02MnO3

ABSTRACT

High temperature electrical conductivity was measured for perovskite La0.98Sr0.02MnO3 at 200~130$0^{circ}C$ as a function of Po2 and 1/T. Perovskite La1-xSrxMnO3 system is the typical oxygen electrode in solid oxide fuel cell (SOFC). Acetate precursors were used for the preparation of mixed water solution and the calcined powders were reacted with Na2CO3 flux in order to obtain highly reactive powders of perovskite La0.98Sr0.02MnO3. The relative density was greatly increased above 90% because of the homogeneous sintering. From the conductivity ($sigma$)-temperature and conductivity-Po2 at constant temperature, the defect structure of La0.98Sr0.02MnO3 was discussed. From the slope of 1n($sigma$) vs 1/T, the activation energy of 0.069 and 0.108eV were evaluated for above 40$0^{circ}C$, respectively. From the relationship between $sigma$ and Po2, it was found that the decomposition of La0.98Sr0.02MnO3 was occurred at 10-15.5 atm(97$0^{circ}C$) and 10-11 atm(125$0^{circ}C$). It is supposed that the improvement of p-type conductivity may be leaded by the increase of Mn4+ concentration through the substitution of divalent/monovalent cations for La site in LaMnO3.