Structural and Magnetic Properties of Pb-substituted CuFe۲O۴ Nanoparticles

Lead-substituted copper ferrites (Cu۱-xPbxFe۲O۴, x = ۰.۰–۰.۳۰) were synthesized via a sol–gel auto-combustion route to explore the structural and magnetic effects of Pb²⁺ incorporation. X-ray diffraction confirmed a tetragonal spinel phase (I۴۱/amd) for low Pb content, which gradually evolved into a pseudo-cubic structure at higher substitution levels. The lattice parameters increased systematically with Pb doping, indicating lattice expansion and suppression of Jahn–Teller distortion. FTIR spectra revealed a red shift of both tetrahedral and octahedral metal–oxygen stretching modes, consistent with elongation of M–O bonds and partial Pb۲+ occupancy of both sites. Magnetic measurements showed soft-ferromagnetic behavior with a notable increase in saturation magnetization (Ms) up to x = ۰.۲۵, followed by a decrease at higher Pb levels due to secondary phase formation and lattice strain. The reduction in coercivity (Hc) with Pb content reflects a weakening of magnetocrystalline anisotropy and lattice relaxation. These results highlight the structural flexibility and magnetic tunability of Pb-substituted CuFe۲O۴, emphasizing the role of large, nonmagnetic cations in controlling spinel ferrite functionality.

کلیدواژه ها:

Spinel Ferrite ، CuFe۲O۴ ، Sol–gel auto-combustion route ، FTIR ، Magnetic behavior