Doping Effect of Y2Ba4CuMoO y Particles on Microstructure and Superconducting Properties in Polycrystalline YBa2Cu3O7−δ
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Synthesis of polycrystalline YBa2Cu3O7−δ (YBCO) + x mol.% Y2Ba4CuMoO y (Y-24Mo1) (x=0.0, 0.1, 0.2, 1.0, 2.0 and 20.0) superconductors have been done in air via a standard solid state reaction technique. The effects of Y-24Mo1 particles on the microstructure and the superconducting transition temperature were systematically investigated through XRD and SEM techniques. When Y-24Mo1 was added to the YBCO, the orthorhombic structure maintained even at the highest concentration. Tiny peaks of Y-24Mo1 having (022) orientation and some other impurity were detected in the XRD spectrum when x=20.0. SEM results reveal the presence of some entities, and these entities changed with increase of Y-24Mo1 content. The Y-24Mo1 addition modifies the normal state resistivity of samples from metallic to semiconducting, and is accompanied by a two-step transition. Moreover, low Y-24Mo1 concentration leads to a relatively sharp superconducting transition and a broad transition take place for Y-24Mo1 addition greater than 0.2 mol.%. These results can be induced by the inhomogeneities, by the change of the effective coupling strength, and by the variation of the coupling between grains.
KeywordsYBCO superconductor Y2Ba4CuMoOy addition Microstructure Superconductivity
This work was supported by the college basic scientific research operation cost of Gansu province (the manufacture and characteristic research of the optical gas sensing film materials and the Y series superconducting materials).
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