Study of ParamagneticCenters in a Series of LaF₃ Nanoparticles with DifferentHydrothermal 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.