Structural characterization of the YBa2Cu3Oσ superconductor with phases [σ=6.87, 6.89 and 6.9] obtained by solid state reaction. - J. M. Juárez-López; M. G. Romero-Sanchez; I. Ponomaryova; G. Castillo-Hernandez; Jose Santos-Cruz; Francisco Javier De Moure-Flores (CCE, 2020)