Defective structure of the ThFe0.2Sn2 and PrFe0.4Sn2 compounds

The defective structure of the PrFe0.4Sn2 and ThFe0.2Sn2 compounds has been studied by 57Fe and 119Sn Mِssbauer spectroscopy, first-principle and binomial distribution calculations. It is shown that the iron and tin sites display different local interactions of atoms located in the same structural position of the defective structure. The analysis of the obtained data together with the theoretical calculations show that defect formation in the samples has a thermal origin. The experimental and theoretical data show that the studied defective structure is locally ordered.