Effect of annealing on structural, textural, thermal, magnetic, and luminescence properties of calcium fluoride nanoparticles

Mesoporous nanocrystalline CaF$_2$ powder was obtained by pulsed electron beam evaporation (PEBE) in vacuum. The specific surface area (SSA) of the nanopowder (NP) of CaF$_2$ reached 88.7 m$^2$g. The effect of thermal annealing in air in the temperature range 200–900$^\circ$C on particle size, morphology, textural, thermal, magnetic, and luminescent properties of NP was studied. A strong deviation of the obtained nanoparticles from stoichiometry and a significant increase in SSA after annealing at 200$^{\circ}$C was observed. The obtained CaF$_2$ NP showed ferromagnetic (FM) behavior. The appearance of the FM response can be explained by the formation of structures and radiation defects. An analysis of the pulsed cathodoluminescence (PCL) curves and the magnetization of NP CaF$_2$ allows us to draw conclusions about their relationship.