We study theoretically the light-induced magnetization switching in a binary ferrimagnet of the type ${\mathrm{A}}_p{\mathrm{B}}_{1-p}$, randomly occupied by two different species of magnetic ions. The localized spins are coupled with spins of itinerant electrons via the $s\text{−}d$ exchange interaction. The dynamics of the localized and itinerant spins is described by coupled rate equations, which include electron-phonon interaction, spin-lattice relaxation, and exchange scattering, induced by the $s\text{−}d$ exchange interaction. The exchange scattering leads to the formation of ferromagneticlike states at initial temperatures $T$ both below and above the magnetization compensation temperature $T_M$ with the opposite polarities in these two temperature regions. Inclusion of electron-phonon interaction and spin-lattice relaxation in the dynamical equations leads to the switching in a temperature range $0<T<T_f$, where $T_f$ is slightly higher than $T_M$ and strongly depends on the spin-lattice relaxation time of itinerant electrons. The switching requires less pulse fluence in the vicinity of $T_M$.

• Received 14 December 2017
• Revised 11 May 2018

DOI:https://doi.org/10.1103/PhysRevB.98.014427