Ion beam mixing of hydrogenated multilayer FeTi and NiTi films

Abstract

Multilayer FeTi and NiTi samples were electrolytically charged with hydrogen to a concentration corresponding to TiH x ( x = 1.5−2.3) in titanium layers. The samples were then bombarded with xenon ions (Xe 2+) at 600 ke V to induce ion beam mixing. Rutherford backscattering and forward recoil spectroscopies were used to probe the changes in the metal and the hydrogen concentrations and profiles respectively. A fluence of 8 × 10 15 Xe 2+ cm −2 caused mixing of uncharged samples of FeTi and NiTi. In hydrogenated samples, however, the mixing was significantly retarded in the FeTi case, whereas NiTi was still completely mixed. This was found to correlate with the release of hydrogen during ion bombardment. The corresponding final hydrogen concentrations were one-half of the initial concentration in FeTi and one-third in NiTi.