On the effect of Cd doping for Ca in La3CaBa3Cu7Oy superconducting cuprate

Enhancement the formation of (Cu, Tl)-1223 superconducting phase by Cd-substitution

“…Since our samples are prepared in sealed quartz tube filled with air instead of vacuum, thus the decomposition of BaO 2 increases the oxygen pressure inside the tube. The reduction in oxygen-content may convert the un-substituted sample, x = 0.0, from over-doped Table 2 The variation of n , Tc, T0 and T with Cd-content for Cu0.5Tl0.5Ba2Ca2−xCdxCu3O 10 region to optimum-doped at about x = 0.2. With further increasing in x the oxygen-content decreases, leading to a suppression in T c for x > 0.2.…”

“…Kandyel [9] investigated Cd-substitution in GaSr 2 (Y, Ca) Cu 2 O 7 cuprate and showed that the substitution induced an orthorhombic-tetragonal phase transition and improved the superconducting properties. Also, Kandyel and Elsabawy [10] proposed that Cd can replace up to 100% of Ca ions in the La 3 CaBa 3 Cu 7 O y high-temperature superconductor compound without affecting the basic crystal structure or forming impurity phases. Parise et al [11] found, from X-ray absorption measurements, that the substitution of Cd 2+ ions for Tl 3+ ions in Tl 2−x Cd x Ba 2 CuO 6+ı did not affect the average oxidation state of thallium in these materials.…”

Superconducting properties of the Sr substituted La3Ca1−xSrxBa3Cu7Oysystem

“…Furthermore, the decrease is gradual until x = 0.4, when an abrupt decrease is observed. It was reported that, when Cd substitutes Ca in La-3137, T c decreases monotonically with increasing Cd content [18]. The authors considered that the difference in the electropositive nature between Cd 2+ and Ca 2+ cations is responsible for the decrease in T c through the reduction of oxygen in the Cu-O chain.…”

The role of sol-gel method and doping Ba in the drastic reduction of the annealing time and the improvement of the coupling between grains of Bi1.6Pb0.4 Sr2-xBaxCa2Cu3Oy superconductor

“…It has been shown that the dependence of ac magnetic susceptibility on the ac field amplitude (Hac) was determined by the pinning strength parameter [7,8]. A tremendous effort has been applied to improve the links between the grains and the properties of the Bi-based superconductor, doping them by various elements such as Pb and Sb [9,10], Ag [11,12], Cd [13,14] and CdO nanoparticles [15].…”