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Titolo: HIGHTEMPERATURE ELECTRICALPROPERTIES OF THE PEROVSKITETYPE OXIDE LA1XSRXMNO3D
Autore: KAMATA H; YONEMURA Y; MIZUSAKI J; TAGAWA H; NARAYA K; SASAMOTO T;
 Indirizzi:
 ISHIKAWAJIMA HARIMA HEAVY IND CO LTD,RES INST,KOUTOU KU,3115 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:
 00223697(1995)56:7<943:HEOTPO>2.0.ZU;27
 Fonte:
 ISI
 Lingua:
 ENG
 Soggetto:
 OXIDATIONREDUCTION BEHAVIOR; SRDOPED LAMNO3; DEFECT STRUCTURE; THERMOELECTRICPOWER; 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., "HIGHTEMPERATURE ELECTRICALPROPERTIES OF THE PEROVSKITETYPE OXIDE LA1XSRXMNO3D", Journal of physics and chemistry of solids, 56(7), 1995, pp. 943950
Abstract
In order to elucidate the conduction mechanism of the perovskitetypeoxide La1xSrxMnO3d (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 O2 gas and as a function of the oxygen partial pressure, P(O2), at 8001100 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 ptype conduction was predominant. The quantity of Q was relatively small in comparison with other perovskitetype 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 multilevel hopping conduction model by calculating the distribution of electrons in highspin and lowspin 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 highspinand lowspin states was smaller than k(B) T, and the calculated hopping mobility gave either a negative activation energy or a negative preexponential 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.
ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/09/20 alle ore 11:18:08