Signatures of room-temperature superconductivity emerging in two-dimensional domains within the new Bi/Pb-based ceramic cuprate superconductors at ambient pressure

We predict the possibility of realizing room-temperature superconductivity in different 2D domains within the ceramic high-Tc cuprates at ambient pressure and experimentally confirm this prediction of 2D room-temperature superconductivity in the newly derived Bi/Pb-based ceramic cuprates containing many grain boundaries, interfaces and multiplate blocks. We argue that, in these high-Tc materials, besides bulk superconductivity in 3D domains there is also strongly enhanced 2D superconductivity emerging in the 3D-2D crossover region well above the superconducting transition temperature Tc. We study the possibility of the existence of distinct 3D and 2D superconducting phases in high-Tc ceramic cuprates, in which the unconventional Cooper pairs behave like bosons and condense below certain critical temperatures into 3D and 2D Bose superfluids in 3D and 2D domains. We show that the superconducting transition temperature in 2D domains is much higher than in 3D domains and can reach up to room temperature. We report signatures of room-temperature superconductivity occurring at different grain boundaries and 3D/2D interfaces and in multiplate blocks within the ceramic superconductors, synthesized by using the new melt technology in a large solar furnace. The samples of these materials synthesized under the influence of concentrated solar energy have the bulk Tc values ranging from 100 K to about 140 K and the more higher superconducting transition temperatures, possibly even as high as room temperature in the 3D-2D crossover region. The remnant 2D superconductivity in newly derived Bi/Pb-based ceramic cuprate superconductors is observed at temperatures 200-300 K well above the bulk Tc and the onset of room-temperature superconductivity is evidenced by the observations of a sharp step-like drop in the resistance and a well-detectable partial Meissner effect at around 300 K and ambient pressure

Temperature dependence investigation of dissipation processes in strongly anisotropic high-temperature superconductors of Bi-Pb-Sr-Ca-Cu-O system synthesized using solar energy

The investigation of temperature dependence of damping and period of vibrations of HTSC superconductive cylinder of Bi-Pb-Sr-Ca-Cu-O system suspended by a thin elastic thread and performing axial-torsional vibrations in a magnetic field at temperatures above the critical one for the main phase Tc=107 K were carried out. It was observed some "chaos" temperature region in the temperature interval 107-138 K, where it is seen separate ripples of dissipation and oscillation frequency. It is assumed that the "chaos" region could point to a possibility of existence of other magnetic and more high-temperature phases as single islands in a normal materials matrix.Comment: 10 pages, 0 figure

Résonance dans alliages des couches supraconductrices refroidi rapidement: (Bi1.7Pb0.3Sr2Can‐1CunO2n+4+δ)2, n=1 to 9détecté par local renforcée atomique XRD

Lien résonance dans alliages supraconductrice à haute température (HTLSC): (Bi1.7Pb0.3Sr2Can-1CunO2n+4+δ)2,n=1-9 appelé (2s:2:n-1:n) préparé en Ouzbékistan à partir de oxide fondu par flux concentré du Soleil, suivi d\u27un refroidissement rapide, technologie SFQA préserve fondre carrelage. Tc,n est mesurée en Tbilissi, et atomique local renforcée synchrotron diffraction des rayons X, (XRD) à proximité de la Cu-K bord est effectuée à DOE National Laboratoire SLAC-SSRL. La structure indexé dans le groupe D17 4h démontre qui (n-1) unîtes: (CuO2)1/2/Ca/(CuO2)1/2 sont intercalés à chaque extrémité de la phase n=1: [(CuO2)1/2/SrO/Bi1.7Pb0.3O/Bi1.7Pb0.3O/SrO/(CuO2)1/2]2. Les effets de surface conduit à intercalations des different n-phase, et à des distorsions réseau périodique (PLD) à travers des effets de résonance de liaison dans le cristal, où (rCu+2 + rO-2)=4.2Å \u3e a=3.82 Å \u3e(CuOorganic+(O=O-O)/23/2)=3.2Å, c1= 26.4Å, et cn-c1= 2(n-1)a + δcn, δcn/(2a(n-1))≈-0.2. Liaisons atomiques locaux des Cu-Ca, Cu-Sr, Cu-O-Cu sont détectés par excitation atomique locale suivie par la réflexion inélastique pour lien trajets. Tc,n est lié à la résonance par l\u27activité chimique de la croissance, ΔG≠ qui prédit Tc,n⇒ 298K quand n⇒50, si la profondeur de la peau supraconducteur est dans cn ≈ quelques microns

Fast melt cooled superconducting alloys: (Bi1.97Pb0.03Sr2Can‐1CunO2n+4+δ)2 n/n’ n\u3c24 intergrowth

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 \u3e a = 3.82Å \u3ed(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)\u3en 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)

Superconductivity at Т≈200 K in Bismuth Cuprates Synthesized Using Solar Energy

When investigating low-frequency (0.1 Hz) oscillations of multiphase high-temperature cuprate superconductors (HTCS) Bi1,7Pb0,3Sr2Ca(n-1)CunOy (n=2-30), a wide attenuation peak (ΔT~100 К) with a maximum at Т≈200 К was detected. This peak was particularly pronounced in field cooling (FC) experiments, i.e. after abrupt cooling of the sample in the external magnetic field at the temperature Т\u3cТс with subsequent slow warming up to room temperature with invariance of the applied field. The attenuation peak height depended on the preliminaryorientation (before cooling) of the samples θ in the measured permanent magnetic field Н. On the one hand, it is well known that, after the FC procedure and subsequent slow warming up, at the temperatures close to the critical temperature Тс, the attenuation peak associated with “melting” of the Abrikosov frozen vortex structure and its disappearance at Т \u3eТс is detected in monophase samples. At the same time, in most multiphase bismuth HTCS samples, synthesized using solar energy and superfast quenching of the melt, the attenuation peak with the maximum at Т≈200 К was observed.Depending on the conditions of synthesis, the attenuation peak could be two-humped and could be located in the temperature range much wider than Тс of the major superconducting phase. We assume that this is due to the existence of frozen magnetic fluxes (after FC) in superconducting “dropping” regions, which gradually (with increasing temperature) transfer into the normal state and release pinned vortex threads. This fact could be a cause of observed dissipative processes, so as also the evidence of the existence of superconductivity at Т ≥240 К