A Mossbauer spectral study of CeFe11Ti and CeFe11TiH

The Mossbauer effect spectra of CeFe11Ti and CeFe11TiH have been measured b etween 85 and 295 K and analyzed in terms of a model which takes into accou nt the local environment of iron on the 8f, 8i, and 8j crystallographic sit es, the influence of the random distribution of titanium on the 8i site, an d 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 hy perfine field and the isomer shift: relative to that observed in its absenc e. A synergistic decrease in the hyperfine fields upon multiple titanium su bstitution is also observed. Upon hydrogenation, both the hyperfine fields and the isomer shifts increase in agreement with the unit cell expansion an d the increased magnetization and Curie temperature of CeFe11TiH as compare d to CeFe11Ti. (C) 1999 Elsevier Science B.V. All rights reserved.