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Effect of sample density on the resistivity and Hall coefficient of polycrystalline La1.83Sr0.17CuO4

The resistivity and Hall coefficient (R(H)) of polycrystalline La1.83Sr0.17CuO4 has been studied as a function of sample density (i.e. porosity). R(H) is inversely proportional to the density and can be corrected to give a good estimate of the in-plane value for single crystals. The resistivity is much more strongly dependent on sample density and grain boundary effects are shown to be important. Bruggeman's symmetrical effective medium theory reproduces some of the features of the density dependence of the resistivity, but is unable to model grain boundary resistances and consequently predicts a percolation threshold at a lower density than is actually observed. It is noted that direct comparisons of cot(theta(H)) between different porous materials is more difficult because of these density dependent behaviours.

electrical resistivity ; Hall effect ; granular superconductivity ; transport-properties. La2-xsrxcuo4 ; temperature ; superconductors ; oxides ; angle

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