Mössbauer Spectral Study of CeFe₁₁Ti and CeFe₁₁TiH

The Mossbauer effect spectra of CeFe11Ti and CeFe11TiH have been measured between 85 and 295 K and analyzed in terms of a model which takes into account the local environment of iron on the 8f, 8i, and 8j crystallographic sites, the influence of the random distribution of titanium on the 8i site, and the insertion of hydrogen into the 2b site of the structure. The presence of titanium in the near-neighbor environment of iron decreases both the hyperfine field and the isomer shift relative to that observed in its absence. A synergistic decrease in the hyperfine fields upon multiple titanium substitution is also observed. Upon hydrogenation, both the hyperfine fields and the isomer shifts increase in agreement with the unit cell expansion and the increased magnetization and Curie temperature of CeFe11TiH as compared to CeFe11Ti