Study of Paramagnetic Centers in a Series of LaF₃ Nanoparticles with Different Hydrothermal Treatment Temperatures

A series of LaF3 nanoparticle samples were synthesized by precipitation from a colloidal solution followed by hydrothermal treatment at temperatures of 120, 160, 200, and 230 °C. An increase in the concentration of paramagnetic centers in LaF3 nanoparticles with an increase in the hydrothermal treatment temperature, along with an increase in the particle size and coherent scattering area, is observed. Paramagnetic centers in a series LaF3 nanoparticles were studied by electron paramagnetic resonance methods. It was shown that most of the paramagnetic centers are concentrated in the particle’s volume. A model of paramagnetic center formation in LaF3 nanoparticles due to the influence of hydrothermal treatment is proposed.