Gadolinium-doped CoFe ₂ O ₄ semi-crystalline nanoparticles with designed morphology: The effect of synthesis parameters on microstructure and magnetic characteristics

In this study, the CoFe ₂ O ₄ nanoparticles were synthesised hydrothermally (70–200 °C) with various molar ratios of CoCl ₂ /FeCl ₃ for desirable nanoparticle shape and properties. The atomic ratios of gadolinium (Gd) were increased to 0.70 to investigate the effect of the Gd dopant. The X-ray diffraction patterns indicated that by increasing the synthesis temperature (70–200 °C), the nanoparticle size decreased from 50.49 nm to 32.45 nm, and the morphology changed from a shapeless and agglomerated state to a spherical shape. The M _s value increased from 17.253 emu/g to 54.438 emu/g with a rise in the synthesis temperature. The effects of the FeCl ₃ / CoCl ₂ molar ratio showed the highest value of M _s (54.438 emu/g) and the coercivity of 744.56 Oe for a 2/1 molar ratio. The X-ray photoelectron spectroscopy illustrated several peaks corresponding to Fe ³⁺ , Co ^{2 +} and O 1. This study aimed to investigate the possibility of utilising CoFe _2−x Gd _x O ₄ nanoparticles for medical treatment.