La2-xSrxCuO4-δ superconducting samples prepared by the wet-chemical method

In this work, we report on the physical properties of good-quality polycrystalline superconducting samples of La2-xSrxCu1-yZnyO4-delta (y = 0, 0.02) prepared by a wet-chemical method, focusing on the temperature dependence of the critical current. Using the wet-chemical method, we were able to produce samples with improved homogeneity compared to the solid-state method. A complete set of samples with several carrier concentrations, ranging from the underdoped (strontium concentration x approximate to 0.05) to the highly overcloped (x approximate to 0.25) region, were prepared and investigated. The X-ray diffraction analysis, zero-field cooling magnetization and electrical resistivity measurements were reported on earlier. The structural parameters of the prepared samples seem to be slightly modified by the preparation method and their critical temperatures were lower than reported in the literature. The temperature dependence of the critical current was explained by a theoretical model which took the granular structure of the samples into account. (C) 2009 Elsevier B.V. All rights reserved.