Modifications of the magnetization ordering in Co/Mo/Co layers by Ga+ ion irradiation

Molecular beam epitaxy-grown layered structures Co/Mo/Co exhibit an antiparallel coupling of Co films magnetization in the Mo spacer thickness range between 0.5 nm and 1.0 nm and parallel beyond this range. Magnetic properties are substantially modified by beam irradiation of 35 keV Ga+ ions. With the increase in ion fluence, antiparallel coupling switches to the parallel one. Further increase in fluence results in gradual suppression of ferromagnetic behavior of the system. Experimental results are correlated with numerical simulations of layered structure evolution driven by irradiation.