Аннотация:The features of the structural, magnetic and magneto-optical properties of thin Zn1-xCoxOy films (x=0-0.3) from 10 to 262 nm thickness, fabricated on с-sapphire substrates by the pulsed laser deposition method are studied. It is revealed that all of the synthesized Zn1-xCoxOy films possess a wurtzite structure with the lattice parameters a = 3.2495 Å, с = 5.2329-5.2485 Å. It is established that the ferromagnetic properties of the Zn1-xCoxOy films nonmonotonously depend on Co concentration at room temperature. For the Zn0.87Co0.13Oy film, the strongest ferromagnetic signal is observed that is caused by formation of the greatest number of metallic Co clusters. A further increase of doping impurity concentration in the films leads to the oxidation of metallic Co and formation of the paramagnetic Co3O4 phase, in consequence of which the ferromagnetic signal subsides. It is defined that the specific magnetic characteristics of the Zn1-xCoxOy samples do not depend on the film thickness. The dependence of the equatorial Kerr effect on cobalt concentration and thickness of Zn1-xCoxOy films was studied for the first time. The magneto-optical signal amplitude is correlated with the film magnetization value.