Sm‐doped yttrium aluminum iron garnet: Structural refinement, magnetic behavior, and dielectric characteristics

Abstract In the present study, the sol–gel auto‐combustion method is used to synthesize Samarium‐doped yttrium aluminum iron garnet (Sm‐YAIG), and the as‐prepared powder was sintered at 1150°C for 10 h. The sintering temperature is confirmed by thermogravimetric and differential thermal analysis (TG/DTA). A single‐phase cubic garnet structure with space group Ia‐ d was confirmed by X‐ray diffraction (XRD) analysis and Rietveld refinement. As expected from Vegard's law, the lattice parameter increased from 12.35 to 12.44 Å with Sm composition varying from x = 0.0 to 2.0. Negative slopes were observed in Williamson–Hall (W–H) plots for all compositions except x = 1.5, indicating the presence of compressive strain. The crystallite size was found to be in the range of 20.39–22.00 nm, which closely matches the values obtained from the Scherrer equation. A redshift of bands at the tetrahedral and octahedral sites was observed due to the incorporation of larger Sm 3 ⁺ ions. The average grain size, particle size, and degree of agglomeration decreased with Sm substitution. The elemental composition was confirmed by energy‐dispersive X‐ray spectroscopy (EDS). The saturation magnetization decreased nonlinearly with Sm content, arising from modifications in Fe–O–Fe bond geometry, partial reinforcement and disruption of super‐exchange interactions, lattice distortion, spin canting, and magnetic dilution. The dielectric constant increased with Sm substitution due to lattice distortions that enhanced interfacial polarization and atomic polarizability. These structural and electronic modifications influenced the properties of Sm‐YAIG, suitable for applications in magnetic sensor technologies and advanced electronic devices.