In this study, Fe2Si thin films were sputtered onto a glass substrate at thicknesses of 100, 200, 300, 400, 500, and 600nm. X-ray diffraction (XRD) was applied to identify film structures. The XRD patterns displayed a Fe2Si (100) significant diffraction peak at 2θ of approximately 25° at room temperature. The surface morphology and grain-size distribution of Fe2Si thin films were observed using a scanning electron microscope (SEM). The authors observed that the crystallization and grain size of thicker Fe2Si thin films were stronger and larger than those of thinner Fe2Si thin films. The Fe2Si (100) texture induced magneto-crystalline anisotropy, thus reducing electrical resistivity and yielding the highest low-frequency alternative-current magnetic susceptibility (χac). The value of χac increased as the thickness was increased because of magneto-crystalline anisotropy. The maximal value of χac was obtained at a thickness of 600nm at the optimal resonance frequency (fres) of 10Hz, which produced maximal spin sensitivity. The resistivity (ρ) decreased as the Fe2Si thickness increased, because grain boundaries and the thin-film surface scattered the electrons; therefore, the thinner films were more resistant. The 600nm-thick Fe2Si thin film exhibited a minimal ρ of approximately 9300Ωcm. The transmission of Fe2Si thin films indicated that the thin Fe2Si film exhibited a high transmittance of approximately 60%. The high transmittance decreased from 60% to 25% as the thickness was increased. Therefore, the optimal Fe2Si thickness was 600nm, yielding the highest χac value of approximately 0.84 with an fres of 10Hz, a minimal ρ of approximately 9300Ωcm, and a transmittance of approximately 25%, because of a strong Fe2Si (100) texture which could be applied in components for a magneto-optical recording medium.