Domain Wall Pinning Sites Introduced by Focused Ion Beam in TbFeCo Film

A method of introducing pinning sites in TbFeCo film by the using of focused ion beam was presented. The formed bulges in the film surface by discontinuous scan of light-dose focused ion beam have been proved to enhance the film's coercivity effectively. Coercivity increases almost linearly with the bulge density, giving the evidence of pinning effect contributed from those bulges predicted by domain wall pinning mechanism. Compared with the traditional way of etching the film for adjusting the coercivity, the method presented here shows superiority on reducing magnetic damage to film caused by the focused ion beam irradiation.