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Competition between structural and electronic factors in (Al/In) doped lanthanum manganites |
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| Authors: | SS Ata-Allah MF MostafaZ Heiba HS Refai |
| Institution: | a Reactor Physics Department, NRC, Atomic Energy Authority, Cairo, Egypt b Physics Department, Faculty of Science, Cairo University, Giza, Egypt c Physics Department, Faculty of Science, Ain Shams University, Cairo, Egypt |
| Abstract: | X-ray structure parameters of La0.7Ca0.3Mn0.96(InxAl(1−x))0.04O3 perovskite manganites determined from the Rietveld analysis of the orthorhombic unit cell, space group Pbnm, showed strong dependence on x. Resistivity (ρ) and ac magnetic susceptibility (χ) measurements showed decrease in the metallic-to-semiconductor transition temperature Tρ and the ferromagnetic-to-paramagnetic Curie temperature TC as x increases. The large drop in Tρ and TC for x=0.0 and 1.0 is ascribed to the difference between the electronic configuration (E-factor) and ionic radius (structure factor) of the dopants and the Mn3+ ions. Decrease in Tρ and TC for samples (0.2<x<0.8) is mainly due to the size mismatch between the A and B sites (structure factor). |
| Keywords: | Manganites Structural parameters Structure factor Electronic factor Double exchange Jahn-Teller effect |
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