Hyperfine fields and local-moment formation at 3<i>d</i>-series impurities in terbium

Abstract

We report the observation of low-temperature nuclear orientation of radioactive Sc, V, Cr, Mn, and Co as extremely dilute impurities in ferromagnetic terbium. A model based on the crystalline anisotropy of Tb and supported by measurements on $^{160}\mathrm{Tb}$ in the same samples was used to extract the hyperfine fields at the 3d impurity sites. Together with the previously known field at FeTb, this essentially completes the systematics for first transition-series impurities in this host; our values for ${B}_{\mathrm{hf}}$ are for ScTb, -2.0(4) T; VTb, -2.4(5) T; CrTb, +11.6(1.0) T; MnTb, +20.0(1.0) T; and CoTb, -2.0(3) T. We discuss the decomposition of these fields into local and transferred contributions and the derivation of local moments from the former.