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Evidence For A Crossover From Multiple Trapping To Percolation In The High-Temperature Electrical Conductivity Of Mn-Doped Lacroo₃, Ryne P. Raffaelle, Harlan U. Anderson, Don M. Sparlin, Paul Ernest Parris
Evidence For A Crossover From Multiple Trapping To Percolation In The High-Temperature Electrical Conductivity Of Mn-Doped Lacroo₃, Ryne P. Raffaelle, Harlan U. Anderson, Don M. Sparlin, Paul Ernest Parris
Materials Science and Engineering Faculty Research & Creative Works
We explain the deep electrical conductivity minimum near x=0.05 in the perovskite-type ceramic LaCr1-xMnxO3 as a crossover between two different regimes of hopping conduction. At low Mn concentrations the diffusion of small polarons among Cr ions is limited by multiple trapping at energetically lower Mn sites. At higher concentrations a percolating path of Mn sites forms and direct transport between Mn ions dominates the conduction process.
Oxidation-Reduction Behavior Of Undoped And Sr-Doped Lamno3: Defect Structure, Electrical Conductivity, And Thermoelectric Power, J. H. Kuo, Harlan U. Anderson, Don M. Sparlin
Oxidation-Reduction Behavior Of Undoped And Sr-Doped Lamno3: Defect Structure, Electrical Conductivity, And Thermoelectric Power, J. H. Kuo, Harlan U. Anderson, Don M. Sparlin
Materials Science and Engineering Faculty Research & Creative Works
Seebeck coefficient and electrical conductivity measurements were performed for undoped and Sr-doped LaMnO3 as a function of temperature and oxygen partial pressure. The results of electrical conductivity showed typical p-type behavior. As reduction proceeded, the electrical conductivity of these LaMnO3-based perovskites decreased with P 1 4O2. The analysis of the electrical conductivity data was performed by extending the defect model from a previous thermogravimetric (TG) study. The measured Seebeck coefficients were found to be positive except for the most reducing conditions when the decomposition into multiple phases occurred. The Heikes formula was adopted to interpret …