Effect of grain connectivity and density on the magnetoresistance in Ca or Li doped lanthanum manganites

X L Wang (Korresp. Autor*in), Peter Gehringer, Wolfgang Lang, Joseph Horvat, H. K. Liu, S X Dou

    Veröffentlichungen: Beitrag in FachzeitschriftArtikelPeer Reviewed

    Abstract

    The effect of grain connectivity on the magnetoresistance (MR) was studied on porous and highly dense polycrystalline bulk samples of La0.7Ca0.3MnO3 and La0.8Li0.2MnO3 synthesised by conventional solid state reaction and partial melting technique. SEM and XRD investigations demonstrated that the partial-melted samples were very dense with large grain sizes whereas the porous sample contained large numbers of small sized grains. The porous La0.8Li0.2MnO3 and highly dense La0.8Li0.2MnO3 samples exhibited a very wide transition width in resistance vs. temperature (R T) plots taken in magnetic fields of 0.3 or 1 T over a wide temperature range from 77 to 235 K. In contrast, the partially melted La0.7Ca0.3MnO3 sample only showed a very sharp transition around the ferromagnetic transition at 235 K in the R T curve. It is proposed that it is the grain connectivity and not the density of the samples that is responsible for the transition width in RT.
    OriginalspracheEnglisch
    Seiten (von - bis)53-56
    Seitenumfang4
    FachzeitschriftSolid State Communications
    Jahrgang117
    Ausgabenummer1
    Frühes Online-Datum14 Nov. 2000
    DOIs
    PublikationsstatusVeröffentlicht - 2001

    ÖFOS 2012

    • 103018 Materialphysik
    • 103009 Festkörperphysik
    • 103017 Magnetismus

    Schlagwörter

    • Magnetically ordered materials
    • Grain boundaries
    • Scanning electron microscopy (SEM)
    • Electronic transport

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