Effect of Pb doping in high-Tc Bi2Sr2CaCu2Oy superconductors studied by X-ray absorption near-edge structure spectroscopy

Internal Oxidation in Bi2.1 − x PbxSr2 − y Ca1 − z Ry + zCu2O8 + d (R = Y, Nd, La) Solid Solutions

“…The localization of holes in the structure of Bi-2212 was established by analyzing the fine structure of the O K absorption edge (the near-edge peak near 528 eV arising from the 3 d 9 L 1 s 3 d 9 transition, where L is a hole localized at the O 2 p x , y orbital [2]). It was found ( Fig.…”

Effect of Pb Substitution on Superconducting and Normal State Electrical Properties of Bi₂Sr₂CaCu₂O_8+σ Nanopowders

“…Doping Pb is an effective method to improve superconducting and flux pinning properties of Bi based superconductor [3]. Beside that, the J c enhancement by Pb doping in Bi 2212 is mainly caused by the increase in hole concentration [4]. It is produced as a granular material, for which the current carrying capacity and the magnetic properties are governed by the currents flowing through the weaklinks between grains.…”

Internal oxidation in Bi2.1 – xPbxSr2 – yCa1 – zYy + zCu2O8 + d solid solutions

“…Information on possible localization of holes in B-2212 was extracted from the fine structure of the O-K edge of absorption band (Figure 2; the pre-peak at 528 eV was attributed to the 3d 9 L ® 1s3d 9 transition, where L is the hole in the O 2p x,y orbital. 2 It was found that the replacement of Bi by Pb did not cause an increase in the hole concentration in a [CuO 2 ] layer, which is responsible for the superconducting properties of the material. The contradiction between the results of chemical analysis and XANES can be resolved taking into account the possibility of electron exchange between [CuO 2 ] and [Bi 2 O 2 ] layers in the structure of Bi-2212.…”