Magnetic relaxation in (Bi, Pb)-2223 superconducting ceramics doped with Æ -Al 2 O 3 nanoparticles - Hernández-Wolpez, M; Gutiérrez-Rivero, L C; Garcia-Fornaris, I; Govea-Alcaide, E; Abud, Fábio Santos Alves; Jardim, Renato de Figueiredo; Muné, P (Revista Mexicana de Física, 2020)