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.
R. P. Raffaelle et al., "Evidence for a Crossover from Multiple Trapping to Percolation in the High-Temperature Electrical Conductivity of Mn-doped LaCroO3," Physical Review Letters, vol. 65, no. 11, pp. 1383-1386, American Physical Society (APS), Sep 1990.
The definitive version is available at http://dx.doi.org/10.1103/PhysRevLett.65.1383
Materials Science and Engineering
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