Gadolinium as a ferromagnetic host for IMPAC experiments

Abstract

The properties of ferromagnetic Gd as a host for IMPAC measurements have been investigated. The transient and internal magnetic fields at Cd, Nd, Sm, Dy, Er, Yb and Hf nuclei recoil implanted into polarized Gd at 80 K have been studied by the IMPAC technique. All available experimental transient field data for Gd have been analysed in the framework of the Lindhard-Winther theory. Empirical values of the parametersv _p andC _ion C _atom have been deduced which give good agreement between experiments and theory. Internal magnetic fields at rare-earth nuclei in magnetized Gd at 80 K have been deduced. The results areH _h.f. (NdGd)=−1370±440 kG,H _h.f.(SmGd)=−1440±120 kG,H _h.f.(DyGd)=1410±400 kG,H _h.f.(ErGd)=2310±420 kG andH _h.f.(YbGd)=−216±32 kG. The signs of these fields are, except for Yb which is in a 2⁺ ionic state, consistent with a ferromagnetic coupling between the 4f spins of the implanted ion and the Gd host. The deduced internal field at Hf in Gd is −440±90 kG. The observed time-dependent interactions for rare-earth nuclei in ferromagnetic Gd are consistent with the Abragam-Pound theory. For the Cd isotopes,g-factors of the first 2⁺ states were deduced from the experiments. The results areg(¹¹⁰Cd)=0.49±0.11,g(¹¹⁴Cd)=0.34±0.09 andg(¹¹⁶Cd)=0.41±0.11. The use of transient magnetic fields forg-factor measurements on high-spin rotational states is discussed.