Effect of laser fluence on magnetic properties of thin Mn$_{x}$Si$_{1-x}$ ($x\approx$ 0.5) films prepared by pulsed laser deposition

The effect of laser pulse energy E on the possibility of forming of a homogeneous “high-temperature” ferromagnetic phase in Mn$_{x}$Si$_{1-x}$ ($x\approx$ 0.5) alloy films grown by pulsed laser deposition onto an Al$_2$O$_3$ (0001) substrate has been studied. The high-temperature phase with manganese concentration $x\approx$ 0.53 and the Curie temperature $T_C\sim$ 200–300 K is shown to form near the substrate at the initial stage of the film growth. In this case, high values $E\ge$ 6.8 J/cm$^2$ favor the stabilization of this phase over all film thickness, while low values $E$ = 2.6–5.7 J/cm$^2$ lead to a decrease in the manganese concentration in the upper film layer and the formation of additional “low–temperature” phase with $T_C\approx$ 30–50 K provided by silicides MnSi and Mn$_4$Si$_7$ crystallites.