2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/40049We comment on the recent preprint hep-ph/0007123 by M.B. Voloshin, claiming that domain walls are diamagnetic. We show that the results presented therein are based on an incorrect treatment of the zero mode contribution to the vacuum energy density. We also shown that the correct treatment leads to the conclusion that domain walls are ferromagnetic, and can generate a primordial magnetic field.4 pages latex (a misprint in Eq.(1) has been corrected)High Energy Physics - PhenomenologyAstrophysicsGeneral Relativity and Quantum CosmologyHigh Energy Physics - Theorytext