Transport and Spectroscopic Properties of Undoped and Zn-Doped Ceramic Superconductors
Structural, transport, and spectroscopic properties of the ceramic superconductor La 2-x Sr 2 CuO 4 and YBa 2 Cu 3 O 7-σ have been investigated as a function of a Cu/Zn-substitution. An increase of the in-plane lattice parameters in a(b) direction and a decrease of the parameter in c direction is correlated to changes in vibrational frequencies for the in plane and out of plane Cu-O stretching modes. T c was found to decrease dramatically with increasing Zn-substitution. For the temperature dependence of the resistivity, Mott’s model for hopping conduction could be applied for the metallic, as well as for the semiconducting temperature and doping range.
KeywordsRoom Temperature Resistivity Mobility Edge Ceramic Superconductor Doping Range Oxygen Doping
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