Influence of the synthetic conditions on the crystal structure, magnetic and optical properties of holmium orthoferrite nanoparticles

In this work, holmium orthoferrite nanoparticles ( o -HoFeO 3 ) were prepared by a straightforward co-precipitation method and annealed at 850 °C for 60 min. The crystal structure, magnetic and optical properties of o-HoFeO 3 samples were considerably different depending on the procedure used for co-precipitation of holmium and iron hydroxides. The hydrolysis of Ho (III) and Fe (III) cations in hot water (t° > 95 °C) increases the crystalline degree and reduces the particle size of the o-HoFeO 3 phase compared with the control sample prepared at room temperature (t° ~ 27 °C). The prepared HoFeO 3 nanoparticles are capable of getting used as photocatalyst materials because of their strong adsorption band at 200–400 nm observed from the UV–Vis spectrum. Additionally, the HoFeO 3 nanoparticles are materials with H c ~ 20–30 Oe, M r ~ 0.01–0.02 emu·g −1 , and M s ~ 4.0–5.0 emu·g −1 . These findings demonstrate their potential use not only as photocatalysts, but also as antiferromagnetic materials.