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Titolo:
HIGH-TEMPERATURE ELECTRICAL-PROPERTIES OF THE PEROVSKITE-TYPE OXIDE LA1-XSRXMNO3-D
Autore:
KAMATA H; YONEMURA Y; MIZUSAKI J; TAGAWA H; NARAYA K; SASAMOTO T;
Indirizzi:
ISHIKAWAJIMA HARIMA HEAVY IND CO LTD,RES INST,KOUTOU KU,3-1-15 TOYOSUTOKYO 135 JAPAN YOKOHAMA NATL UNIV,INST ENVIRONM SCI & TECHNOL,HODOGAYA KU YOKOHAMA KANAGAWA 240 JAPAN KANAGAWA INST TECHNOL,DEPT CHEM TECHNOL ATSUGI KANAGAWA 24302 JAPAN
Titolo Testata:
Journal of physics and chemistry of solids
fascicolo: 7, volume: 56, anno: 1995,
pagine: 943 - 950
SICI:
0022-3697(1995)56:7<943:HEOTPO>2.0.ZU;2-7
Fonte:
ISI
Lingua:
ENG
Soggetto:
OXIDATION-REDUCTION BEHAVIOR; SR-DOPED LAMNO3; DEFECT STRUCTURE; THERMOELECTRIC-POWER; SEEBECK COEFFICIENT; STABILITY; NONSTOICHIOMETRY; CONDUCTIVITY; RESISTIVITY;
Keywords:
OXIDES; ELECTRICAL CONDUCTIVITY; ELECTRICAL PROPERTIES; ELECTRONIC STRUCTURE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
23
Recensione:
Indirizzi per estratti:
Citazione:
H. Kamata et al., "HIGH-TEMPERATURE ELECTRICAL-PROPERTIES OF THE PEROVSKITE-TYPE OXIDE LA1-XSRXMNO3-D", Journal of physics and chemistry of solids, 56(7), 1995, pp. 943-950

Abstract

In order to elucidate the conduction mechanism of the perovskite-typeoxide La1-xSrxMnO3-d (0 less than or equal to x less than or equal to0.4), the electrical conductivity, sigma, and Seebeck coefficient, Q,were measured as a function of temperature, T, up to 1100 degrees C in 1 atm O-2 gas and as a function of the oxygen partial pressure, P(O-2), at 800-1100 degrees C. At T > similar to 200 degrees C, sigma T increased with T, indicating that thermally activated type conduction may predominate irrespective of x. The Q values were generally positive,indicating that p-type conduction was predominant. The quantity of Q was relatively small in comparison with other perovskite-type oxides, implying that these materials are metallic, irrespective of whether the conduction is thermally activated or itinerant. The relationship between sigma and Q for x less than or equal to 0.2 can be interpreted interms of a multi-level hopping conduction model by calculating the distribution of electrons in high-spin and low-spin levels of Mn3+ and Mn4+ using statistical dynamics. For x = 0.3 and 0.4, a calculation based on this model revealed that the energy difference between high-spinand low-spin states was smaller than k(B) T, and the calculated hopping mobility gave either a negative activation energy or a negative pre-exponential factor, suggesting that the hopping model is not applicable and that the electrons are itinerant. The electronic nature of the oxides therefore changes from localized to itinerant between x = 0.2 and x = 0.3.

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Documento generato il 30/09/20 alle ore 11:18:08