Magnetic easy-axis switching in Pt/Co/Pt sandwiches induced by nitrogen ion beam irradiation

The effect of N+ ion irradiation on the magnetic anisotropy of ultrathin Co films in the Pt/Co(1 nm)/Pt (111) system is investigated. The magneto-optical measurements indicate that the as-deposited trilayers display a perpendicular magnetic anisotropy whose properties drastically change with the fluence in the range of 1012 to 1016 ions/cm2. The coercive field progressively decreases as the fluence increases. The superconducting quantum interference device measurements evidence that, for the highest fluences, the paramagnetic limit is not reached moreover an in-plane switching of the anisotropy is observed. Simulations are performed to evaluate damage energy induced by N+ irradiation