Enhancement of the recoilless fraction in R2Fe10Co4Si2 (R=Gd, Er, Y) offstoichiometric compounds after hydrogenation

Samples of R2Fe10Co4Si2 (R=Gd, Er and Y) solid solutions were prepared by arc melting and exposed to hydrogenation. Characterization of hydrogenation effects was done using Mössbauer spectroscopy. The values of the magnetic hyperfine fields corresponding to the four inequivalent lattice sites were found to increase after hydrogenation in all offstoichiometric compounds investigated. Slight changes in the relative site occupancies were observed. Transmission Mössbauer spectra were also recorded for absorbers consisting of the intermetallic and the stainless steel etalon. The recoilless fraction was derived from these spectra using the method developed by us. Our study is the first to evidence that the recoilless fraction is enhanced after hydrogenation.