Akademik Veri Yönetim Sistemi
JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS, cilt.15, ss.229-234, 2013 (SCI-Expanded)
Bi2Pb0.5Sr2Ca4Cu6LixHoxOy (0.0 <= x <= 0.5) samples were prepared by doping with Li and Ho at changing ratios and using melt-quenching method. Thus, the influences of different doping levels of Li and Ho on the structural and electrical properties of the BPSCCO compound have been investigated by electrical resistivity, Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Energy Dispersive X-Ray Spectroscopy (EDX) techniques. It has been observed that, with increasing Li and Ho doping, the high-T-c Bi-(2223) phase gradually transforms into the low-T-c Bi-(2212) and Bi-(2201) phases. However, It should be pointed out that these low-T-c superconducting phases are formed at all the doping levels, but increasing amount with increasing concentration of Li and Ho. Therefore, while the electrical resistivities in the normal states increase, the superconducting transition temperatures, T-c, hole concentrations, p, and the magnitudes of thermoelectric powers of all the samples decrease with increasing Li and Ho concentration x. As a result, the results suggest that with the increase in Li and Ho amount the superconductivities of all the samples are suppressed due to the destruction of the phase coherence by pair-breaking effects, or, to the hole filling mechanism with increasing x.