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

X L Wang; Peter Gehringer; Wolfgang Lang; Joseph Horvat; H. K. Liu; S X Dou

doi:10.1016/S0038-1098(00)00402-6

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

X L Wang (Corresponding author), Peter Gehringer, Wolfgang Lang, Joseph Horvat, H. K. Liu, S X Dou

Publications: Contribution to journal › Article › Peer Reviewed

Abstract

The effect of grain connectivity on the magnetoresistance (MR) was studied on porous and highly dense polycrystalline bulk samples of La_0.7Ca_0.3MnO₃ and La_0.8Li_0.2MnO₃ 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 La_0.8Li_0.2MnO₃ and highly dense La_0.8Li_0.2MnO₃ 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 La_0.7Ca_0.3MnO₃ 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 R−T.

Original language	English
Pages (from-to)	53-56
Number of pages	4
Journal	Solid State Communications
Volume	117
Issue number	1
Early online date	14 Nov 2000
DOIs	https://doi.org/10.1016/S0038-1098(00)00402-6
Publication status	Published - 2001

Austrian Fields of Science 2012

103018 Materials physics
103009 Solid state physics
103017 Magnetism

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10.1016/S0038-1098(00)00402-6

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@article{6cec320cbff04355bf14ba53114c614f,

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

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 R−T.",

keywords = "Magnetically ordered materials, Grain boundaries, Scanning electron microscopy (SEM), Electronic transport",

author = "Wang, {X L} and Peter Gehringer and Wolfgang Lang and Joseph Horvat and Liu, {H. K.} and Dou, {S X}",

year = "2001",

doi = "10.1016/S0038-1098(00)00402-6",

language = "English",

volume = "117",

pages = "53--56",

journal = "Solid State Communications",

issn = "0038-1098",

number = "1",

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TY - JOUR

T1 - Effect of grain connectivity and density on the magnetoresistance in Ca or Li doped lanthanum manganites

AU - Wang, X L

AU - Gehringer, Peter

AU - Lang, Wolfgang

AU - Horvat, Joseph

AU - Liu, H. K.

AU - Dou, S X

PY - 2001

Y1 - 2001

N2 - 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 R−T.

AB - 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 R−T.

KW - Magnetically ordered materials

KW - Grain boundaries

KW - Scanning electron microscopy (SEM)

KW - Electronic transport

U2 - 10.1016/S0038-1098(00)00402-6

DO - 10.1016/S0038-1098(00)00402-6

M3 - Article

SN - 0038-1098

VL - 117

SP - 53

EP - 56

JO - Solid State Communications

JF - Solid State Communications

IS - 1

ER -

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

Abstract

Austrian Fields of Science 2012

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