Mössbauer spectral study of NdFe1-xGaxO3NdFe1-xGaxO3 perovskites

The 57Fe Mossbauer spectra of NdFe1-xGaxO3NdFe1-xGaxO3 (x=0x=0, 0.1, 0.2, 0.25, 0.5 and 0.7) have been measured at room temperature (RT). For x<0.5x<0.5 the spectra have been fitted with magnetic sextets with their areas following a binomial distribution of Fe surroundings with Ga neighbours. The spectra for x=0.5x=0.5 and 0.7 show paramagnetic doublets, which account for the percolation effect induced by the non-magnetic Ga substitution for Fe, which has been estimated to be x=0.43x=0.43 at RT. The analysis of the hyperfine field values as a function of the Ga concentration shows the effect of the variations of the antiferromagnetic sublattice magnetization. Moreover, the dependence of this field with the number of susbstituted neighbours suggests an increase of the average Fe–O–Fe exchange interaction as a consequence of the lattice contraction when Ga susbtitutes for Fe.