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Author Taran, Subhrangsu ♦ Sun, C. P. ♦ Yang, H. D. ♦ Chatterjee, S.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY ♦ CONCENTRATION RATIO ♦ CRYSTAL-PHASE TRANSFORMATIONS ♦ DOPED MATERIALS ♦ ELECTRICAL PROPERTIES ♦ LANTHANUM COMPOUNDS ♦ LATTICE PARAMETERS ♦ LITHIUM ADDITIONS ♦ LITHIUM COMPOUNDS ♦ MAGNETIC PROPERTIES ♦ MANGANATES ♦ MIXING ♦ ORTHORHOMBIC LATTICES ♦ POLARONS ♦ POWDERS ♦ SYMMETRY ♦ TEMPERATURE RANGE 0273-0400 K ♦ TRIGONAL LATTICES ♦ X-RAY DIFFRACTION
Abstract A detail study of transport and magnetic properties of La{sub 1-x}Li{sub x}MnO{sub 3+δ} (0.05 ≤ x ≤ 0.3) system synthesized by wet-chemical mixing route has been done. The room temperature x-ray powder diffraction (XRD) data show single phase behavior of all samples except x = 0.3. Rietveld refinement of XRD data shows structural transition from rhombohedral (R3-C) to orthorhombic (Pnma) symmetry occurs at the Li-doping level x > 0.2 with both the lattice parameter and unit-cell volume decrease with increase of ‘x’. All the samples show ferromagnetic (FM) behavior while metallic behavior are shown by the samples up to Li-concentration x = 0.2. With further Li doping i.e. for x = 0.25, the sample shows insulating behavior accompanied by charge-order transition around T ~ 225 K. Metallic part of the resistivity data of the samples is best fitted with an expression ρ(T) = ρ{sub 0} + ρ{sub 4.5}T{sup 4.5} + C/ sinh{sup 2}(hv{sub s}/2k{sub B}T) containing small-polaron contribution (last term). Most interesting finding in the present study is the observation of large anomalous decrease in thermoelectric power (S) below 100 K shown by the sample with x = 0.25. Probable mechanisms responsible for the observed colossal thermoelectric power have been discussed.
ISSN 0094243X
Educational Use Research
Learning Resource Type Article
Publisher Date 2016-05-23
Publisher Place United States
Volume Number 1731
Issue Number 1


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