Anisotropy in RFe2 Intermetallics: An NMR Study

Abstract

The anisotropy of the Ho3+, Tb3+ and Tm3+ rare-earth ions in RFe2 compounds is investigated using the field dependence of the NMR spectra of 169Tm, 159Tb and 165Ho in polycrystalline TmFe2, TbFe2, HoFe2 and related pseudo-binary compounds. The very large hyperfine interaction in these ions dominates the NMR spectrum; the NMR frequencies in the 2 to 7 GHz range provide therefore a measure of the localized moment and its orientation in the crystal field. We compare the NMR measurements to single ion computations that include magnetostriction. KEYWORDS:

Investigation of the Direction of Spontaneous Magnetisation at 0 K in HoCo2 and TmFe2

“…For TmFe 2 most of the experimental data available would indicate that the <110> is the orientation of spontaneous magnetization at all temperatures; therefore the parameters given by Yanovsky et al [15] are probably incorrect. However, the analysis given by Sariri, based on unpublished high field 169 Tm:TmFe 2 nmr [23] and in some pseudo-binary alloys would indicate that magnetostriction is not negligible. An extra term needs to be included in the crystal-field Hamiltonian in order to take the magnetostriction distortion into account.…”