A structural transformation and its effect on the physical properties of the V-substituted system

Abstract

Systematic substitution of V in the system , 0.2, 0.4, 0.6, 0.8 and 1) was carried out in order to determine the effect of V ions on the phase formation and on the physical properties of the BSCCO 2223 system. The most interesting observation was structural transformation of the system from tetragonal to orthorhombic after . A solid solubility limit for V was also found to exist. Resistivity and susceptibility studies have shown that high- superconductivity exists up to and that the semiconducting-to-metallic transition or fully semiconducting behaviour occurs after this limit. A fractionally small but very-high- transition at around 210 K was also observed, but it was not reproducible. Among the V-substituted samples the best electrical properties were obtained for ; and were found to be 112 K and 92 K, respectively, the calculated value of was found to be at 4.5 K and the thermal conductivity parameter was found to be . By substituting the higher-valence state ions for , the thermal treatment time is significantly reduced. The magnetic properties, IR and thermal conductivity results showed evidence of a strong coupling mechanism in the system.

Synthesis and characterization of Er-substituted Bi-2223 H-Tc glass–ceramic superconductors

“…In the last decade, there were many investigations have been made on κ(T) of high-T c materials [26][27][28][29][30][31][32][33][34][35][36][37] and almost the same results were obtained. In general, for κ(T) investigation of high-T c materials three important approaches can be considered to the total κ(T) calculations: (i) phonon contribution; (ii) electron contribution; and (iii) both electron and phonon contributions.…”

“…Thermal conductivity, κ(T), investigation also gives important information about the scattering mechanism of charge carriers, electron-phonon interaction and other physical properties such as carrier density and phonon mean free path [26][27][28][29][30][31]. In the last decade, there were many investigations have been made on κ(T) of high-T c materials [26][27][28][29][30][31][32][33][34][35][36][37] and almost the same results were obtained.…”

Thermal and superconducting properties of glass–ceramic HTc BiSrCa(CuPr)O system

“…After a small minimum, a sharp rise with a maximum and then a sharp drop were obtained just below T c . Such a feature has been observed in most substituted and/or unsubstituted HT c systems (Chanda and Dey, 1994;Bougrine et al, 1998Bougrine et al, , 2000Aksan et al, 1999;Yakıncı, 1997). The origin of this small minimum near T c is not clear but may be attributed to superconducting fluctuation contribution (Castellazi et al, 1997;Peacor et al, 1991;Yu et al, 1992).…”

Effect of Mo substitution on the structural and transport properties of Bi2Sr2Ca2Cu3−xMoxO10+y system

“…2a). Most of the plate type crystals were considered to be c-axis oriented (according to the XRD investigations) and material has low porosity compared with the undoped BSCCO system [36]. The microqualitative analysis showed that plate type crystals were compositionally in the Bi 1.97 Sr 1.98 Ca 1.17 Cu 1.61 Mo 0.44 O 8+y form (the error is less than 1%).…”

“…As in the metals and alloys the κ(T) investigations gives important information about the scattering mechanism of charge carriers, electron-phonon interactions and some other physical properties such as carrier density and mean free path [30][31][32][33][34][35][36]. Many investigations have been made on κ(T) properties of HT c materials and similar results were obtained [30][31][32][33][34][35][36][37][38][39][40][41][42]. But the results obtained for κ(T) calculations showed an unusual behavior compared to the conventional metallic structures [31,[37][38][39][40][43][44][45][46].…”