2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/29087We propose a novel approach to the problem of a transition from quantum to classical behavior in mesoscopic spin systems. This paper is intended to demonstrate that main cause of such transitions is quantum decoherence which appear as a result of a thermal interaction between spin system and its environment.2 pages, 1 figure, submitted to Phys Stat Sol RRNMesoscale and Nanoscale Physicstext