Effect of lead substitution in bismuth-based cuprate systems containing both low-Tcand high-T

Abstract

We report the results of resistivity, ac-susceptibility, and specific-heat measurements carried out on samples of Bi& Pb Sr~Ca2Cu30&0+"(O~x~0 .7) that were characterized by x-ray diffraction and high-resolution scanning tunneling microscopy. The zero resistance temperature, T, (R=O), shows a peak at x =0.3 and the susceptibility data indicate that although a high-T, 2:2:2:3 phase is present at 110 K, there is a second transition at 90 K that seems to indicate the existence of an additional low-T, 2:1:2:2phase. The specific-heat data unambiguously indicate a clear and distinct anomaly around T, for samples with x =0.3-0.4 and smearing of the anomaly for x )0.5. Based on the results obtained from these combinations of experiments, the role of lead substitution in Bi samples, particularly in the stabilization of the 2:2:2:3phase has been discussed.

NaCl-Type Oxide Films Prepared by Plasma-Enhanced Metalorganic Chemical Vapor Deposition

“…It is now well known that there are three different superconducting phases in Bi-based superconductors with T c s around 10 K (n = 1, Bi-2201), 85 K (n = 2, Bi-2212) and 110 K (n = 3, Bi-2223) as reported widely [1][2][3]. The Bi-2223 phase has attracted considerable interest due to its higher T c and potential for applications requiring high critical current densities J c .…”

PHYSICAL CHARACTERIZATION OF PURE AND SUBSTITUTED TETRAGONAL LaBaCaCu3O7-δ SUPERCONDUCTOR

“…Any alteration in these superconducting stacks, even at the microscopic level affects the superconductivity drastically. 25,[58][59][60][61] The c-parameters of unit cells of the most of highly an-isotropic HTSc systems are larger than their coherence length in the same direction. Large c-parameters of HTSc systems do not permit any magnetic interaction between RE moments and the superconductivity in Cu-O 2 planes.…”

“…72 In RE based HTSc families, the RE:123 and RE:124 had widely been exposed to the 3d metal substitutions. 25,[58][59][60][61][62] The RE:247 compound is a sum of RE:123 and RE:214 compounds in terms of its structure and some of physical properties. 70,71 Relatively less known RE:1113 compound, with RE = La as its main member, is a prototype of RE:123 system, with 40 at% of usual La-site occupied by Ca and the Ba-site is intermixed with both Ca and La ions, see Sec.…”

IMPACT OF Zn SUBSTITUTION ON PHASE FORMATION AND SUPERCONDUCTIVITY OF Bi1.6Pb0.4Sr2Ca2Cu3-xZnxO10-δ WITH x = 0.0, 0.015, 0.03, 0.06, 0.09 AND 0.12

“…In this regards, Cu-site partial substitution of Zn 2+ has attracted a lot of attention since from the invention of HTSC [3][4][5][6]. The size of square planer Cu in Cu-O 2 planes marches well with that of Zn 2+ hence the partial substitution can take place without much changing the lattice parameters of the doped system [3][4][5][6][7].…”

“…Zn substitution in HTSC was considered to be anomalous and most interesting in the beginning of HTSC invention itself, in particular due to the reason that the substitution of magnetic divalent ion Ni at Cu-site showed five times smaller T c depression rate than that of non-magnetic ion Zn 2+ at the same site [4][5][6][7][8]. Cu/Zn substitution of around more than 1at% [19,20].…”