A new method for the formation of a diluted magnetic semiconductor based on gallium arsenide doped with iron and manganese atoms is considered. The method consists in diffusion doping during pulsed laser deposition in vacuum. Using the method of X-ray photoelectron spectroscopy, the profile of the chemical elements distribution was obtained. The magnetic phases influence on the behavior of the magnetic field dependence of the Hall resistance is analyzed. The technological parameters for the growth of the structure exhibiting ferromagnetic properties at room temperature were selected.