2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/97371We report results demonstrating a singularity in the hysteresis of magnetic materials, the reversal-field memory effect. This effect creates a nonanalyticity in the magnetization curves at a particular point related to the history of the sample. The microscopic origin of the effect is associated with a local spin-reversal symmetry of the underlying Hamiltonian. We show that the presence or absence of reversal-field memory distinguishes two widely studied models of spin glasses (random magnets).3 pages, 5 figures. Proceedings of "2002 MMM Conferece", Tampa, FLDisordered Systems and Neural Networkstext