Variable-range hopping conductivity and absence of a true metal–insulator transition in La0.7−δ Ca0.3Mn1−yFeyO3
Resistivity of La0.7−δ Ca0.3Mn1−yFeyO3 (LCMFO) with y=0–0.05, δ=0 and 0.017 is investigated between 4.2–350 K, showing that La vacancies increase the effect of Fe doping by influencing electronic states through additional microscope disorder. The Shklovskii–Efros variable-range hopping conductivity,...
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Veröffentlicht in: | Journal of applied physics 2002-05, Vol.91 (10), p.7400-7402 |
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Hauptverfasser: | , , , , , , , |
Format: | Artikel |
Sprache: | eng |
Online-Zugang: | Volltext |
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Zusammenfassung: | Resistivity of La0.7−δ Ca0.3Mn1−yFeyO3 (LCMFO) with y=0–0.05, δ=0 and 0.017 is investigated between 4.2–350 K, showing that La vacancies increase the effect of Fe doping by influencing electronic states through additional microscope disorder. The Shklovskii–Efros variable-range hopping conductivity, governed by generation of a soft parabolic gap in the spectrum of localized states due to Coulomb interaction between charge carriers, is observed both above and well below the ferromagnetic-to-paramagnetic transition temperature. Our results give evidence for absence of a true metal–insulator transition both in undoped material and in LCMFO. |
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ISSN: | 0021-8979 1089-7550 |
DOI: | 10.1063/1.1448300 |