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Presentation
Fast melt cooled superconducting alloys: (Bi1.97Pb0.03Sr2Can‐1CunO2n+4+δ)2 n/n’ n<24 intergrowth
Almaden Institute (2012)
  • J. Kmiec, San José State University
  • Juana Vivó Acrivos, San José State University
  • D. D. Gulamova, Academy of Sciences of Uzbekistan
  • J. G. Chigvinadze, E. Andronikashvili Institute of Physics
Abstract
High temperature layer superconducting cuprate (HTLSC) alloys: (Bi1.97Pb0.03Sr2Can-1CunO2n+4+δ)2 called (2s:2:n-1:n) have been grown from n-oxide stoichiometric melts in concentrated sun flux, followed by rapid cooling SFQA technology that preserves the melt tiling after annealing at 845±5oC**. Synchrotron XRD at the DOE SLAC-SSRL near the Cu K-edge has identified the mixing of n ≠ n’ alloys as observed by many in thin films last century. An ideal D17 4h Space Group structure obtains {an, bn, cn} = {3.815 Å, an+ubn, 2dP(n+3)+ucn} where dP is a perovskite sandwich, (CuO2)1/2|_Ca|(CuO2)1/2, thickness, and un are the amplitudes of periodic lattice distortions, PLD also observed last century*. Many electron interactions lead to covalent bonds indicated by 2(rCu+2+rO-2) =4.2Å > a = 3.82Å >d(CuO)+2-3/2d(O3)). Thus n-nano clusters grow n-1 perovskite sandwiches confined within a hard shell
(CuO2)1/2|OSr|Bi1.97Pb0.03O|OBi1.97Pb0.03|SrO|(O2Cu)1/2. Disproportion reactions produce n’=Nn+3(N-1)>n clusters that are supported by n cluster pillars (fig. 1). The increase in the transition temperature to the superconducting state was determined by axial-torsional vibration measurements in transverse magnetic fields that obtain Tc⇒190K as n increases in ppm emergent regions***. n, n’ alloy mixtures identify Cu-Ca, Cu-Sr, Cu-O-Cu strong bond scattering. Example shows that enhancement at Q0=[11(n+3)]n=4,(n’=12)=2.53/Å is also detected at Q*=[1116]12, [1029]12 near Cu K-edge due to Cu-M bond back scattering that identify M=Ca, Sr, O, Cu (Table I, fig. 2).
Disciplines
Publication Date
October, 2012
Location
San Jose, CA
Comments
This poster was presented at the Almaden Institute in 2012.
Citation Information
J. Kmiec, Juana Vivó Acrivos, D. D. Gulamova and J. G. Chigvinadze. "Fast melt cooled superconducting alloys: (Bi1.97Pb0.03Sr2Can‐1CunO2n+4+δ)2 n/n’ n<24 intergrowth" Almaden Institute (2012)
Available at: http://works.bepress.com/juana_acrivos/138/