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). Fe-57 Mossbauer 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. (C) 2012 Elsevier Inc. All rights reserved.