Dependence of the Gd concentration range for thermally induced magnetization switching on the intrinsic damping

Abstract

Ultrafast magnetization switching induced by a single femtosecond laser pulse in the absence of an applied magnetic field has attracted extensive attention due to its great potential for low energy and ultrafast storage applications. However, pulse helicity-independent switching is mainly used for Gd-based materials, and it is now necessary to explore the possibility of further optimization depending on the composition and damping coefficients. For the GdFe alloy with low Gd concentration, we modulate the damping constant for a comparative analysis based on atomic spin simulations. The simulation results show that an appropriate increase in the high damping ratio αFe/αGd not only helps to extend the pulse fluence range for switching but also reduces the minimum Gd concentration requirement for transient ferromagnetic-like state. The results show that the pulse fluence threshold of switching at low Gd concentration is more sensitive to the damping ratio αFe/αGd. On the contrary, modulating the damping ratio αFe/αGd at high Gd concentrations almost does not cause the shift of pulse fluence threshold. The lower Gd concentration for thermally induced magnetization switching is expected to be unlocked by the engineering of element-specific damping.