tailieunhanh - A close correlation between disorders defects and superconducting transition temperature of Bi1.6Pb0.4Sr2Ca2-xNaxCu3O10+δ superconductors

The enhancements of zero superconducting transition temperature (Tc,0) in xNaxCu3O10+δ (BPSCCO) are reported. The BPSCCO samples (with x ranging from to ) were prepared by using the conventional solid state reaction technique. | Vietnam Journal of Science and Technology 56 (1A) (2018) 41-49 A CLOSE CORRELATION BETWEEN DISORDERS-DEFECTS AND SUPERCONDUCTING TRANSITION TEMPERATURE OF SUPERCONDUCTORS Tran Hai Duc1, *, Nguyen Khac Man2, Dang Thi Bich Hop3 1 Faculty of Physics, VNU University of Science, 334 Nguyen Trai, Ha Noi, Viet Nam 2 International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology, 1 Dai Co Viet, Ha Noi, Viet Nam 3 Faculty of Basic Sciences, University of Transport Technology, 54 Trieu Khuc, Ha Noi, Viet Nam * Email: dhtran@ Received: 15 August 2017; Accepted for publication: 30 March 2018 ABSTRACT The enhancements of zero superconducting transition temperature (Tc,0) in (BPSCCO) are reported. The BPSCCO samples (with x ranging from to ) were prepared by using the conventional solid state reaction technique. The properties of the samples were examined by using the X-ray diffraction (XRD), scanning electron microscopy (SEM), and the resistance versus temperature (R-T) measurements. From the XRD resuts, all samples revealed the orthorhombic structure, and the volume fraction of the Bi-2223 phase was varied as increasing x, and reached the maximum value of % for x = sample. Improvements of connectivity between the Bi-2223 grains in the Na-substituted BPSCCO samples were obtained by using the surface SEM images and a quantitive analysis of a correlation between Tc,0 and residual resistance ratio (RRR). A similar variation of T c,0 of the samples as increasing x was observed. The highest Tc,0 enhancement of K was obtained for x = sample. Variations of the hole carrier concentrations in the CuO2 layers were investigated, which also showed the highest value achieved for x = sample. Keywords: BPSCCO, Bi-2223, Tc,0, RRR 1. INTRODUCTION In recent years, studies on applications of high temperature superconductors (HTS) have been .