This paper presents the results of a study on the structural and hysteresis properties of iron-containing thin films fabricated by magnetron sputtering and molecular beam epitaxy. The kinetics of oxide formation on film surfaces during thermal oxidation were investigated. In air-oxidized permalloy films, NiFe2O4 oxides and amorphous iron oxyhydroxide groups predominantly formed as the thermomagnetic treatment temperature increased. At higher annealing temperatures, the surface oxides on permalloy films consisted mainly of iron oxides (primarily α-Fe2O3). In iron films annealed at 250°C, only hematite (α-Fe2O3) was observed. The dependence of hysteresis properties on annealing temperature was established, and conditions for exchange bias in oxidized permalloy films were identified. In contrast, iron films exhibited no hysteresis loop shift, likely due to the low magnetic anisotropy of hematite.