title: Tuning A-site ionic size in R(0.5)Ca(0.5)MnO3 (R = Pr, Nd and Sm): robust modulation in dc and ac transport behavior.
abstract: Structural investigations on Pr(0.5)Ca(0.5)MnO(3), Nd(0.5)Ca(0.5)MnO(3) and Sm(0.5)Ca(0.5)MnO(3) display a systematic tuning in orthorhombic distortion which appears due to a change in A-site ionic size. Comprehensive investigations on dc conduction using various models indicate strong correlation with structural changes. Careful analysis of the ac conductivity mechanism as a function of frequency and temperature brings out a pronounced effect of structural modifications on the polaron conduction mechanism. Contrary to typical manifestations, dc conductivity and relaxation of charge carriers reveal non-Arrhenius behavior. This work provides a detailed and systematic addition to the phase diagram of electronic transport in the rare-earth manganite system doped with a divalent alkali atom.
authors: Department of Solid State Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
authors: A
authors: A
authors: Karmakar
authors: S
authors: S
authors: Majumdar
authors: S
authors: S
authors: Giri
mesh_terms: D004553:Electric Conductivity; D007477:Ions; D008280:Magnetics; D017895:Manganese Compounds / Q000737:chemistry*; D008956:Models, Chemical; D008962:Models, Theoretical; D013696:Temperature
chemical_list: D007477:Ions; D017895:Manganese Compounds; C494384:manganite