Phase transformation of [Co/Ti]x10 multilayer under swift heavy ion irradiation.

Swift heavy ions induced structural and magnetic modifications of Co/Ti multilayers have been studied with 120 MeV Ag⁹⁺ ions at different ion fluences. The decrease in 1st Bragg peak intensity of X-ray reflectivity spectra confirms an increase in Co-Ti mixing at the interfaces, whereas X-ray diffraction (XRD) measurements reveal amorphization of the crystalline Co layer. XRD also indicates a shift in peak position towards a lower angle, confirming the development of tensile stress upon irradiation whereas an increase in the peak width suggests the reduction in the grain size. Vibrating sample magnetometer measurements show a reduction in M_r/M_s due to Co-Ti interface mixing and formed bcc-Co₃Ti metastable phase. The X-ray absorption fine structure (XAFS) technique has been utilized to obtain variation in Co-Co and Co-Ti bond distances as a function of ion fluences. Quantitative estimation of Co₃Ti phase generated due to ion irradiation has also been obtained using Co K-edge XAFS fitting. [ABSTRACT FROM AUTHOR]