Enhancement in Curie temperature of yttrium iron garnet by doping with neodymium

The effect of the substitution of Y³⁺ by Nd³⁺ on the structural and magnetic properties of neodymium-doped yttrium iron garnet, Nd_xY_3-xFe₅O₁₂ with x in the range of 0-2.5, is presented. Oxide powders of Fe₂O₃, Nd₂O₃, and Y₂O₃ were mixed in a stoichiometric ratio and milled for 5 h using high-energy ball milling, before being uniaxially pressed at 900 MPa and annealed at 1373 K for 2 h to obtain Nd_xY_3-xFe₅O₁₂ (0 ≤ x ≤ 2.5). It was found that the mechanical milling of oxides followed by annealing promotes the complete structural formation of the garnet structure. Additionally, the X-ray diffraction patterns confirm the complete introduction of Nd³⁺ into the garnet structure with a neodymium doping concentration (x) of 0-2.0, which causes a consistent increment in the lattice parameters with the Nd³⁺ content. When x is higher than 2.0, the yttrium orthoferrite is the predominant phase. Besides, the magnetic results reveal an increase in the Curie temperature (583 K) as the amount of Nd³⁺ increases, while there was enhanced saturation magnetization as well as modified remanence and coercivity with respect to non-doped YIG.