Morphological analyses of Hg1-xHoxBa2Ca2Cu3O8+y (0.0 <= x <= 0.20) superconductors fabricated by sol-gel technique

Abstract

This work reports a systematic study on the morphological properties of the superconducting compounds, Hg1-xHoxBa2Ca2Cu3O8+y with 0.0 <= x <= 0.20, prepared by using the so-called sol-gel method fallowed by a sealed quartz tube synthesis. The analyses of the synthesized products were performed by XRD, AFM, SEM and EDX methods. The results, obtained from the analyses of the XRD and EDX spectra or patterns, and the SEM and AFM images, indicate that the high-T-c Hg-(1223) and Hg-(1234) phases gradually disappear with increasing amounts of Ho. In addition it is observed that, Hg is excluded from the structure with the addition of Ho for Hg. As a result, it has been concluded that the high-T-c phases, Hg-(1223) and Hg-(1234), gradually disappear with increasing amount of Ho content, due to the exclusion of excess amount of Hg from the structures of the samples. This exclusion and observation may be attributed either to the quite different sizes of Ho and Hg ions or to the large HgO powders compared to the sol-gel powders and/or even to the sample preparation method used in this work.