Structural, thermal and magnetic properties of orthoferrite holmium nanoparticles synthesized by a simple co-precipitation method

In this study, holmium orthoferrite ( o -HoFeO 3 ) nanoparticles were successfully synthesized by simple co-precipitation method without adding gelling organic polymers. Structures, morphologies, elemental composition, thermal, and magnetic properties of the product were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), thermogravimetry and differential scanning calorimetry (TG-DSC), and vibrating sample magnetometer (VSM). After annealing the precursors at different temperatures for 60 min, nanocrystrals with orthorhombic perovskite structure were obtained. Crystallite size ( D PXRD = 22.13–53.74 nm), particle size ( D TEM/SEM = 20–60 nm), and lattice volume ( V = 223.65–224.99 Å 3 ) increased with the annealing temperature. The optimal annealing temperature for obtaining the single crystalline phase of o -HoFeO 3 was ≥ 750 °C, and the o -HoFeO 3 crystalline phase remained stable at temperatures ≥ 1050 °C. The synthesized o -HoFeO 3 nanoparticles exhibited a uniform spherical shape, with a size of 20–60 nm, and exhibited the properties of a paramagnetic material at 300 K. Notably, the coercive force and residual magnetism of the synthesized material were much smaller than those reported in previous studies for similar materials. The experimental results in this work may provide fundamental support to the research and development of magnetic material.