Laser-induced demagnetization in a MAX phase (Cr0.5Mn0.5)2GaC

Abstract

Magnetic MAX phases are nanolaminated metals that combine ceramic-like thermal and mechanical stability with peculiar magnetic ordering, making them attractive for thin-film optoelectronics and spintronics. However, laser-induced magnetization dynamics in MAX phases remains largely unexplored. Here, we investigate laser-induced ultrafast demagnetization in a 40-nm-thick epitaxial film of the magnetic MAX phase (Cr0.5Mn0.5)2GaC, which magnetically orders below ~220 K, using time-resolved magneto-optical Kerr effect spectroscopy. We reveal, that the demagnetization transients exhibit a two-step type-II demagnetization, common for two-dimensional magnetic systems. The second stage dominates the process and has a characteristic time of approximately 100 ps. Applying the three-temperature model, we extract the electron-lattice, spin-lattice, and electron-spin coupling constants. The reconstructed spin heat capacity exhibits a weak temperature dependence, accounting for only a subtle slowing down of demagnetization at elevated temperatures and fluences.