Intrinsic Properties of Ternary Rare-Earth Compounds from 57Fe, 161Dy, 166Er Mössbauer Spectroscopies

Abstract

57Fe, 161Dy and 166Er Mossbauer results are reported in the R2Fe14B alloys and some of the corresponding hydrides. The local moments at the six inequivalent iron crystallographic sites are inferred from the 57Fe hyperfine field data. The occurrence of fairly pure Jz = 15/2 state at the two Dy and Er sites is demonstrated from the near free ion values of the rare-earth hyperfine fields. Empirical estimates of the second order crystal field parameters are provided by the 161Dy quadrupole interaction data. Informations on the magnetic structures and spin reorientation phenomena are obtained from the study of magnetically oriented samples. A detailed analysis of the spin reorientation in (Er1-xDyx) 2Fe14B alloys allowed to estimate the importance of higher order crystal field terms (B4 0, B6 0). The study of the R1+eFe4B4 phases indicated that the iron atoms are essentially non-magnetic and revealed the occurrence of a giant value for the crystal field parameter A2 0. The magnetic properties of the Nd (Co1-xFex)9Si2 alloys, inferred by combining bulk measurements with Mossbauer and NMR data, are presented.