Improvement of T_c, Unit Cell Volume, and Meissner Effect in High-Temperature Superconductors

¹ Materials, Signals, Systems and Physical Modeling Laboratory, Faculty of Sciences, Ibnou Zohr University, Agadir, Morocco
² Energies and Sustainable Development Research Team (E2D), Higher School of Technology, Guelmim, Ibnou Zohr University, 81000, Morocco

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

In this paper, experimental research is done on resistivity, AC magnetic susceptibility, and X-ray diffraction. This work examines two heat treatments: [O] and [OA], Oxygen and Oxygen-Argon annealing respectively. [OA] heat treatment raises T_c for x>0.2, the orthorhombicity ε for x varying between 0 and 1 and reduce the d(Ba/Sr-Cu(1)) (interatomic distance) for x>0.2. Under any applied magnetic field and for T < T_c, the [OA] samples exhibited a significant enhancement in the shielding effect (Meissner effect), as reflected by the amplitude of χ′(Τ). The Meissner factor S(x) decreases for all x values when either T or H_dc increases. Correlations were noted between p_Sh(x) (the number of holes) and T_c (x), within the superconducting plans Cu(2)-O₂, and the unit cell volume V(x) on the other hand. The observed results could be explained by any of these causes, which include a reduction in d(Ba/Sr-Cu(1 )), an improvement in the ordering of cations and chain oxygen, as well as an increase in the in-phase purity of the [OA] samples.