[en] In this work we studied temperature dependent magnetization processes in nanocrystalline Fe₈₆Zr₇B₆Cu₁. Ribbons produced by melt-spinning in air, were submitted to fast dc Joule heating in vacuum to induce a nanocrystalline α-Fe phase. In order to investigate the untrivial interplay between structural and magnetic properties, hysteresis curves were measured as a function of temperature, with particular attention to the magnetic hardening effect. Details of the magnetization process were analyzed by using the Preisach model of hysteresis. (orig.)