Influence of the lanthanum deficit on electrical resistivity and heat capacity of silver-doped lanthanum manganites La{sub 1-x}Ag{sub y}MnO{sub 3}

Journal Article · Tue Dec 15 00:00:00 EST 2009 · Journal of Experimental and Theoretical Physics

DOI:https://doi.org/10.1134/S1063776109120103· OSTI ID:21443642

Gamzatov, A G ^[1]; Mel'nikov, O V; Gorbenko, O Yu ^[2]

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1. Russian Academy of Sciences, Amirkhanov Institute of Physics, Dagestan Scientific Center (Russian Federation)
2. Moscow State University (Russian Federation)

The electrical resistivity and heat capacity of the silver-doped lanthanum manganites La{sub 0.80}Ag{sub 0.15}MnO{sub 3} and La{sub 0.85}Ag{sub 0.15}MnO{sub 3} have been investigated. Despite the nonstoichiometry of the composition, the La{sub 0.80}Ag{sub 0.15}MnO{sub 3} manganite exhibits a bulk homogeneity and better physical properties from the applied point of view as compared to the La{sub 0.85}Ag{sub 0.15}MnO{sub 3} manganite, viz., the former compound has a higher spontaneous magnetoresistance and a larger jump of the heat capacity with a small width of the phase transition, and the anomalies of the heat capacity and electrical resistivity in the vicinity of the Curie point of this compound agree with the fluctuation nature of the second-order phase transition. The behavior of the properties of lanthanum-deficient manganites under investigation in the region of the phase transition is consistent with the classical theory of indirect exchange interaction. The behavior of the temperature dependence of the electrical resistivity has been analyzed in terms of two models. One of these models is based on the tunneling of charge carriers between ferrons or polarons, and the other model is based on the polaron hopping conduction. Both approaches lead to consistent results, and their combination has made it possible to estimate the tunneling distance of charge carriers. The origin of the influence of technological parameters characterizing the synthesis of La{sub 1-x}Ag{sub y}MnO{sub 3} ceramic materials on their physical properties has been elucidated.

• OSTI ID: 21443642
• Journal Information: Journal of Experimental and Theoretical Physics, Vol. 109, Issue 6; Other Information: DOI: 10.1134/S1063776109120103; Copyright (c) 2009 Pleiades Publishing, Ltd.; ISSN 1063-7761
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CERAMICS
CHARGE CARRIERS
CURIE POINT
DOPED MATERIALS
EXCHANGE INTERACTIONS
FLUCTUATIONS
LANTHANUM COMPOUNDS
MAGNETORESISTANCE
MANGANATES
PHASE TRANSFORMATIONS
POLARONS
SILVER ADDITIONS
SILVER COMPOUNDS
SPECIFIC HEAT
TEMPERATURE DEPENDENCE
TUNNEL EFFECT
ALLOYS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
INTERACTIONS
MANGANESE COMPOUNDS
MATERIALS
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
QUASI PARTICLES
RARE EARTH COMPOUNDS
SILVER ALLOYS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT ALLOYS
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
VARIATIONS