2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/134073We use spin-density-functional theory to study recently reported hysteretic magnetoresistance ρ_{xx} spikes in Mn-based 2D electron gases [Jaroszyński et al. Phys. Rev. Lett. (2002)]. We find hysteresis loops in our calculated Landau fan diagrams and total energies signaling quantum-Hall-ferromagnet phase transitions. Spin-dependent exchange-correlation effects are crucial to stabilize the relevant magnetic phases arising from distinct symmetry-broken excited- and ground-state solutions of the Kohn-Sham equations. Besides hysteretic spikes in ρ_{xx}, we predict hysteretic dips in the Hall resistance ρ_{xy}. Our theory, without domain walls, satisfactorily explains the recent data.4 pages, 4 figures, published version (some changes to the text; same figures as in v1)Mesoscale and Nanoscale Physicstext