Effect of Buffer Gases on the Energy Spectrum of Laser Plume Particles during Laser Ablation of a SiMn Binary Target

We have studied the effect of He, Xe, Ar, and N₂ buffer gas pressure on the energy spectrum of particles in the plasma plume during ablation of a SiMn binary target by nanometer laser pulses. Time-of-flight Langmuir probe measurements have been used to find velocity distribution functions of charged plume particles in relation to the type and pressure (10^–6 to 4 × 10^–1 Torr) of the gas. We examined possible mechanisms of the nonmonotonic effect of gas pressure on the probe signal amplitude and delay. Argon and nitrogen as buffer gases have been shown to have little effect on the energy of particles in a wide pressure range. Varying the argon pressure from 10^–5 to 8 × 10^–2 Torr changes the peak signal arrival delay by 20%, which allows the properties of the films we prepared to be varied gradually. The ferromagnetic resonance signal amplitude of Mn_xSi_1–x (x ~ 0.5) films has been shown to depend on argon pressure.