Effect of he+ ion irradiation on interface width in thin-film co/pt terahertz spintronic sources

In this work, we experimentally studied the structural modification of the interfaces in bilayer Co/Pt spintronic terahertz emitters under irradiation with He+ ions with a fluence of up to 1016 cm-2. Using the non-destructive method of small-angle X-ray reflectometry, an increase in the Co/Pt interface width from 1.2 nm (initial sample) to 1.9 nm under irradiation with He+ with a fluence of 1016 cm-2 was detected. The experimental data are in good agreement with the results of modeling using SRIM. The magneto-optical measurements showed that the samples retain their magnetic properties at all fluences. The results can be used to increase the efficiency of terahertz generation in such structures.