Ion-induced phase transition in thin Co films

Abstract Rectangular 75 nm thick Co films were irradiated with 200 keV Xe-ions, to fluences of 2.5×10 13 –8×10 15  ions/cm 2 . The film thickness and the implanted Xe profiles, the phase structure and ion-induced lattice dilations as well as the magnetic hysteresis patterns were measured. For lower fluences up to 4×10 14  Xe/cm 2 , we found predominantly the HCP phase with an in-plane magnetization. The transition to the four-fold in-plane magnetization typical of the FCC phase occurred at a fluence range between 4×10 14 /cm 2 and 2×10 15 /cm 2 .