Ion-induced phase transition in thin Co films

Rectangular 75 nm thick Co films were irradiated with 200 keV Xe-ions, to fluences of 2.5×1013–8×1015 ions/cm2. 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 4×1014 Xe/cm2, 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 4×1014/cm2 and 2×1015/cm2. [Copyright &y& Elsevier]