Conversion electron Mossbauer spectroscopy was used to study the thin films obtained by co-precipitation of coatings from two sources: magnetron sputtering of a metal tantalum target and thermovacuum evaporation of metallic iron enriched in the 57Fe isotope. The films of required thickness were formed by alternating exposure to a magnetron-generated tantalum flow and a flow of iron vapor from a thermal evaporator. The analysis of the Mossbauer spectra showed that co-precipitation of iron atoms transferred to the vapor state by heating and tantalum atoms from the magnetron plasma forms a solid solution of iron in tantalum. The film structure is mainly a metastable β-modification of tantalum of the tetragonal crystal system. Annealing of the samples at 1100°С led to the transition of the β-tantalum structure into the body-centered cubic structure of the α-modification of tantalum. It is found that magnetron sputtering creates favorable conditions for formation of solid solutions of two metals at temperatures far from the melting temperatures of their components.