Erbium-Induced modifications in the structural, magnetic, and dielectric properties of gadolinium iron garnet

Erbium-doped gadolinium iron garnet (Er-GIG) nanoparticles were synthesized via the sol–gel auto-combustion method and sintered at 1150 °C for 10 h. XRD with Rietveld refinement confirmed a single-phase cubic garnet structure (space group Ia-$\overline{3}$d), with decreasing lattice parameter and increasing crystallite size (15.56 – 20.47  nm) as Er content increased (x = 0.0 – 2.0). Structural distortion due to the smaller Er³⁺ ions is evident in FTIR and Raman spectra. Density measurements revealed improved densification, while FE-SEM and HR-TEM analyses showed grain growth (104 – 204  nm). Magnetic measurements indicated enhanced saturation magnetization and reduced coercivity with Er substitution. Dielectric studies exhibited frequency-dependent behavior consistent with the Maxwell–Wagner model. The simultaneous improvement in magnetic and dielectric properties is attributed to Er-induced lattice distortion, cation redistribution, and strengthened Fe³⁺– O^2- –Fe³⁺ super-exchange interactions. These microstructural and electronic modifications make Er-GIG a promising candidate for applications in magnetic sensors and electronic devices.