Modification of magnetization orientation in Pt/Co/Pt ultrathin films by femtosecond laser pulses

Abstract

Ultrathin Pt/Co/Pt films were irradiated with femtosecond laser pulses of sufficiently high energy to create irreversible structural and in consequence magnetic modifications. The effect was studied as a function of an initial structure of the Co film, determined by different temperatures during preparation of the Pt buffer layer, and a Co film thickness, which determines the initial out-of-plane or in-plane magnetization orientation. A creation of many magnetic phases is shown. The out-of-plane magnetization state is found to be created for significantly broader fluence range for the Co film deposited on the Pt buffer layer grown at 750°C in comparison to that grown at room temperature. Reversible magnetization dynamics was also studied in the low fluence regime, using a pump-probe setup. The results were discussed using simulations of temperature dynamics.