Electrical transport properties of the rare-earth ion substituted (Ti, Ps)Sr1.6Ba0.4(Ca0.8R0.2)Cu2Ox superconducting system

✍ Scribed by Q. Hong; Jui H. Wang

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 345 KB
• Volume: 214
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(93)90828-e

✦ Synopsis

Systematic studies on the electrical transport properties of a series of rare-carth (RE) ion substituted (TI, Pb)Srl.6Bao.4(Cao.sRo.z)Cu2Ox superconductors are performed by measuring the transport critical temperature T,. and critical current density Jc. It is found that the substituted samples by trivalent RE elements exhibit similar 7%' s ( ~ 99 K), which are much higher than that of the unsubstituted sample ( ~ 73 K). However, the sample doped by the same amount of Tb shows a small change in Tc while that of the Ce doped sample decreases dramatically from that of the unsubstituted material. We attribute this effect to the mixed valence of RE ions. The J~ does not vary significantly from sample to sample for materials exhibiting a high T c, indicating that the magnetic moment of the unpaired 4f-electrons has essentially no effect on the scattering of superconducting carriers. The Jc of the unsubstituted material has been found to be 1.7× l0 s A/cm 2 at 4.2 K in the absence of an external field. which represents the highest Jr achieved in Tl-based polycrystalline superconductors so far. The results are also compared with those obtained in the RE substituted YBCO and BSCCO systems.