The effect of MgO addition on the formation and the superconducting properties of the Bi2223 phase

Magnetic properties of superconducting ceramics Bi 1.6 Pb 0.4 Sr 2 Ca 2 Cu 3 O 10+d prepared by different methods

“…These analysis have shown that after the final sintering, sample 1 presents, besides the Bi( Figure 1 shows the AC susceptibility versus temperature χ′(T) measured with zero applied magnetic field. The three samples have the same temperature of transition T c ≈ 107 K. When for sample 2 and sample 3, χ' show a second transition at lower temperature indicating traces of Bi(Pb)-2212 phase [6], for sample 1 the second apparent transition indicate the more pronounced presence of weak links or coupling transition [11]. The temperature of the second transition in that sample is too low to be correlated with the Bi(Pb)-2212 phase.…”

“…In Bi(Pb)-2223 tapes made from Bi(Pb)-2212 precursors, the powder calcination temperature has an influence on the sintering temperature leading to the maximum critical current density [4]. Enhanced critical current densities have been obtained by induced Cr-ion defects [5] on Bi(Pb)-2223 tapes and MgO addition on Bi(Pb)-2223 powder [6]. The critical current density may be obtained by transport or magnetic measurements.…”

Superconducting Properties of Mo2Re3Bx-Mo3Re2BxEutectic

“…Indeed, Mo 2 Re 3 B x lamellas embedded in the Mo 3 Re 2 B x matrix, which is normal above 6.6 K, can be regarded as a granular superconducting system. For percolating granular systems there are always two superconducting transitions [11][12][13]. First, at higher temperature a set of grains undergoes into superconducting state, next the set percolates and the grains form larger superconducting clusters at lower temperature.…”

“…more than 1 K below the main transition in the eutectic sample. It is a common behaviour of microwave absorption in granular systems because the Josephson junctions become superconducting at lower temperature than the one of grains [11]. Junctions suffer also from a spread of transition temperatures.…”

Effects of nano‐Al 2 O 3 particles on the superconductivity of Pb‐doped BSCCO

“…In this case, nanosize secondphase particles must be trapped within the superconducting grains and become therefore a second-phase defects. There are several report results of improved J c values through introducing nanometer particles such as SiC, MgO, ZrO 2 , Al 2 O 3 and SrZrO 3 [1][2][3] into high T c superconductors. Most of these studies reported that nanometer-scale inclusions were mainly observed to form aggregates between lamellae, act thus as barriers and hinder the grain growth.…”