Synthesis and Physicochemical Properties of Magnetic Fe3O4 Particles Doped with Gd(III)

Magnetic Fe₃O₄ nanoparticles (NPs) were synthesized by alkaline precipitation from aqueous solutions of divalent and trivalent iron salts. Synthesis of Fe_3-xGd_xO₄ NPs (x = 0.05; 0.1) was performed by adding a calculated amount of Gd(NO₃)₃·6H₂O to the initial solution of iron salt mixture. The phase composition and magnetic properties of the synthesized powders were investigated by X-ray diffraction analysis, ⁵⁷Fe Mössbauer spectroscopy and vibration sample magnetometry at temperatures T = 7, 20 and 300 K. The investigations confirmed the formation of NPs of non-stochiometric Fe_3-δO₄ magnetite, as well as magnetite doped with Gd³⁺ ions. The correlation between the average diameter of NPs of the initial Fe_3-δO₄ powder and doped Fe_3-xGd_xO₄ powder and the salt used in the synthesis, as well as the concentration of Gd (x), respectively, was revealed.