Soft-x-ray absorption spectroscopy ofNd1+xBa2

OK-edge and CuL23-edge XANES study on the concentration and distribution of holes in the(Pb2/Karppinen1, Kotiranta2, Yamauchi3 et al. 2001Phys. Rev. BSelf Cite214170View full textAdd to dashboardCite

“…The peak at ϳ528.3 eV is assigned to the transition from the O 1s state to the O 2p hole state in the CuO 2 plane, in line with the interpretations earlier made for the Cu-1212 and Bi-2212 phases. [2][3][4][5][6][7][8][9][10][11] The peak at ϳ530.4 eV might be due to a superposition of O 2p hole states in the SrO and PbO-Cu-PbO layers and the upper Hubbard band. The pre-edge peaks were analyzed by fitting with Gaussian functions.…”

“…So far, XANES measurements-both O K-edge and Cu K-and L 23 -edge studies-have been most intensively applied for establishing changes in site-specific hole concentrations of the CuA 2 QCu 2 O 6ϩz or Cu-1212 phase, i.e., the distribution of holes among the superconductive CuO 2 plane and the charge-reservoir CuO z chain, with varying cationsubstitution level and/or oxygen content. [2][3][4][5][6][7][8][9][10] Note that, Cu-1212 is nothing but the so-called ''123'' phase. Also note that in the present contribution ''z'' is used instead of ''1 Ϫ␦'' for the amount of excess oxygen.…”

Neutron structural studies on the superconducting (Nd1−xCax)(Ba1.6La0.4)Cu3Oz system

“…Therefore, neutron diffraction data on all samples were refined on the basis of a tetragonal structure ͑space group P4 / mmm͒. Neutron scattering factors used were ͑in units of femtometers͒ 8 …”

“…Superconductivity is suppressed due to the localization of holes. [6][7][8] Accompanying the LR 3+ substitution on the Ba 2+ site is a change in the crystal structure from orthorhombic to tetragonal ͑O-T͒ and an increase in the flatness of the CuO 2 plane. 9 A comparison of substituting magnetic ions ͑such as Eu 3+ , Pr 3+ , Nd 3+ ͒ ͑Refs.…”

Effects of Slight Non-Stoichiometry in Sm-Ba-Cu-O Systems on Superconducting Characteristics

“…proposed by Kramer et al [20,21], according to which the increase of the Sm content of x results in an increase of the total oxygen content and a decrease in the hole concentration in Cu-O 2 planes by donate electrons of the substitution. Sm 3+ entering Ba 2+ sites leads to a non-fourfold planar coordinated Cu on the chain sites either by the introduction of extra oxygen or oxygen reordering, relocation of oxygen from chain O(1) to the O(5) vacancy site.…”