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Metallic and semi-conducting resistivity behaviour of La0.7Ca0.3−xKxMnO3 (x = 0.05, 0.1) manganites | ||
| Journal of Theoretical and Applied Physics | ||
| مقاله 7، دوره 9، شماره 1، خرداد 2015، صفحه 45-58 اصل مقاله (586.78 K) | ||
| شناسه دیجیتال (DOI): 10.1007/s40094-014-0159-z | ||
| نویسندگان | ||
Dinesh Varshney  ؛ Neha Dodiya
| ||
| Materials Science Laboratory, School of Physics, Vigyan Bhawan, Devi Ahilya University | ||
| چکیده | ||
| AbstractThe temperature dependence of electrical resistivity, ρ, of ceramic La0.7Ca0.3−xKxMnO3 (x = 0.05, 0.1) is investigated in metallic and semi-conducting phase. The metallic resistivity is attributed to be caused by electron–phonon, electron–electron and electron–magnon scattering. Substitutions affect average mass and ionic radii of A–site resulting in an increase in Debye temperature θD attributed to hardening of lattice with K doping. The optical phonon modes shift gradually to lower mode frequencies leading to phonon softening. Estimated resistivity compared with reported metallic resistivity, accordingly ρdiff. = [ρexp. − {ρ0 + ρe−ph (=ρac + ρop)}], infers electron–electron and electron–magnon dependence over most of the temperature range. Semi-conducting nature is discussed with variable range hopping and small polaron conduction model. The decrease in activation energies and increase in density of states at the Fermi level with enhanced Ca doping is consistently explained by cationic disorder and Mn valence. | ||
| کلیدواژهها | ||
| Magnetic materials؛ Ab initio calculations؛ Electrical properties؛ Phonons | ||
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آمار تعداد مشاهده مقاله: 54 تعداد دریافت فایل اصل مقاله: 28 |
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