Possible Sources of Trigger Mechanism of Electron-phonon Interactions in Doped CuTl-1223 Superconductors

This article underlines the important role of copper Cu(3d9) spins at the CuO2 planer sites to comprehend the physics of High temperature Superconductivity . In such studies we have reported the characterization results of samples (Cu0.5Tl0.5)Ba2Ca2Cu3O10-δ , (Cu0.5Tl0.5)(BaCa)(CaMg)Cu1Zn2O10-δ , (Cu0.5Tl0.5)(BaCa)(CaMg) Zn3O10-δ and (AyTl1-y)(BaCa)(CaMg) Zn3O10-δ (A=Ag, K, Ni, Mn; y=0,0.5). Samples were prepared at normal pressure by using two-steps solid state reaction method. The characterization of samples is done via x-ray diffraction (XRD), resistivity (RT) and Fourier Transform Infrared (FTIR) absorption measurements. Intrinsic superconducting parameters and activation energy of all sample is estimated applying two theoretical models, Fluctuation Induced conductivity (FIC) analysis and Mott 3D-VRH. The XRD and FTIR absorption measurements have confirmed the intrinsic doping of K, Ag, Ni, Mn and Zn. Interestingly, samples (Cu0.5Tl0.5)(BaCa)(CaMg) Zn3O10-δ without CuO2 planes have exhibited superconducting behavior above 77K. To verify the role of Cu(3d9) atoms in superconductivity we have synthesized (AyTl1-y)(BaCa)(CaMg) Zn3O10-δ (A=Ag, K, Mn, Ni; y=0,0.5) samples. In aforementioned samples, doping of Ni, Mn, K, Ag ions in Cu1-xTlxBa2O4-δ charge reservoir layer instead of Cu-atoms destroys the superconductivity completely and leads to semiconducting behavior. Key objective to preparing these samples is to investigate the role of two major parameters local moments (spin) of copper atoms and net carrier’s concentration in superconductivity.

A Cr(IV) based 1212-type cuprate

ABSTRACTBy means of high pressure and high temperature we have prepared a new material similar to the classic YBa2Cu3O7 (Ybacuo) superconductor but having chromium in the so-called charge reservoir layer: CrSr2YCu2O8. It has been characterised by different techniques such as X-ray diffraction, TEM, ED, EDS, and magnetic susceptibility. The new material is isostructural with the Ru equivalent compound (RuSr2YCu2O8). An antiferromagnetic transition is observed on cooling below 130 K. The as prepared material is not superconducting down to 4 K.