Directional effects of heavy-ion irradiation in Tb/Fe multilayers

Deposition of a Fe-57 probe layer at the top of iron layers in Tb/Fe multil ayers has allowed us to study locally the atomic mixing induced by high-ene rgy heavy-ion irradiation at the Tb-on-Fe interface. The structural and mag netic transformations induced by ion irradiation of the probe layer were in vestigated by Fe-57 conversion electron Mossbauer spectrometry. To study di rectional effects of the ion beam, we have irradiated a stack of two pieces of the same multilayer set face to face. No change in the average composit ion of the mixed Tb-on-Fe interface was observed when the incident ion dire ction is changed from a Tb layer to a Fe layer, or from a Fe layer to a Tb layer.