[en] Full text: Nanocrystalline metallic glasses with compositions FeCuNbSiB (FINEMET) type have attracted attention due to the excellent magnetic properties that present in their nanocrystalline state as low coercive force, low core loss and high permeability [1]. Nanocrystalline thin films are one of the key components in development and manufacture of spintronics-based nanodevices for use in amplifiers, oscillators, diodes, field sensors, memories and magnetic logic, which in turn can be applied to the energy, security, defense and health. Obtaining FINEMET phase in thin films does not have a clearly defined route to date. The usual route, starts from alloys with typical compositions Fe₇₄CulNb₃Si_13,5B_8,5,Fe₇₃Cu₁Nb₃Si_15,5B_7,5 and Fe₇₃CulNb₃Si_16,5B_6,5 or similar [2-3]. The nanocrystalline state of thin films is obtained by annealing of the amorphous alloy at suitable temperatures and times, where the formation of a mixed crystalline structure α-FeSi surrounded by remaining amorphous matrix [2]. The crystallization of FINEMET phase is being investigated from different nanometric thicknesses deposited on silicon (100) and (111) substrates, as well as quartz and glass with different annealing temperatures. The results obtained were investigated by X-ray diffraction as well as by absolute measurements of saturation magnetization and indicate possible crystallization of the FINEMET phase. (author)