In this paper we presented the study of magnetic hysteretic properties, domain structure and microstructure of thin magnetic La-Co films. In the composition range from 9 to 20 at. % La, a beveled hysteresis loops in the plane of the films and stripe domain structure were observed, which are characteristic features of perpendicular magnetic anisotropy. In our work we demonstrated that the columnar microstructure of such films leads itself to the formation of stripe domains, which can be interpreted as the appearance of structure-induced perpendicular magnetic anisotropy. For these purposes, a computer micromagnetic model of the films was developed, and a qualitative agreement between the simulation results and experimental data was obtained.