Mossbauer spectroscopy study of substituted rare-earth iron garnets at low temperature

In this article, we present the results of Mossbauer spectroscopy measurements on the alloys: (A) (Ho0.3Y2.7)Fe5O12, (B) (Ho1.5Y1.5)Fe5O12; and (C) Tb3Fe5O12. The spectra are collected at 4.2 K and at room temperature (RT). Mossbauer spectra of samples A and B show the presence of two magnetic sextets corresponding to iron atoms in octahedral a and in tetrahedral d sites. The spectrum for sample C at RT shows two magnetic sextets with hyperfine fields significantly smaller than those for samples A and B. This reduction in hyperfine field is associated with fast magnetic relaxations in Tb-iron garnet (TIG) at room temperature. At liquid helium temperature, the spectrum of TIG shows three magnetic sextets. Two of these are associated with the canted spin structure at low temperature. (C) 2002 Elsevier Science B.V. All rights reserved.