2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/144505Introducing a variable cosmological parameter $Λ(t)$ in a geometrical manner from a 5D Riemann-flat metric, we investigate the origin and evolution of primordial magnetic fields in the early universe, when the expansion is governed by a cosmological parameter $Λ(t)$ that decreases with time. Using the gravitoelectromagnetic inflationary formalism, but without the Feynman gauge, we obtain the power of spectrums for large-scale magnetic fields and the inflaton field fluctuations during inflation. A very important fact is that our formalism is {\em naturally non-conformally invariant}.7 pages, no figuresHigh Energy Physics - Theorytext