Effect of Gd substitution on the structure and magnetic properties of YFeO3 ceramics

High quality Gd-doped YFeO3 polycrystalline samples were synthesized by solid-state reaction method. The crystal structure of the samples can be described by the space group of Pbnm (No. 62). 57Fe Mössbauer spectra show that only the high spin Fe3+ exists and the samples are magnetic ordering at room temperature. The spontaneous magnetization at room temperature was observed and the paramagnetic contribution from Gd3+ ions was confirmed by the significant enhancement of the magnetization. Temperature-dependent magnetization data correlate with the Gd concentration x and follow the Curie–Weiss law above the ferromagnetic transition temperature. Magnetic measurements suggest that the substitution of Y3+ ions by Gd3+ ions effectively enhance the magnetization of YFeO3. This is achieved by the additional Gd–Gd interactions, Gd–Fe interactions and the variation of Fe–O–Fe superexchange bond caused by distortion of the crystal structure.