A comparative study of the hyperfine fields in ferromagnetic GdRh and GdZn

Abstract
The zero‐field nuclear resonance of Gd155, Gd157, Rh103, and La139 were studied in Gd1−xLaxRh. Magnetic measurements performed on GdRh show that this compound has a Curie temperature of 24 K and a magnetization corresponding to 6.6μB/Gd at 4.2 K. These values are low compared with those of GdZn (270 K; 7.5μB/Gd). The NMR results of Gd1−xLaxRh are compared with similar data available for Gd1−xLaxZn. For both series the hyperfine field at the Gd site is separated into its different contributions. The transferred hyperfine field at the Gd site is positive in GdRh but negative in GdZn. It is suggested that the exchange interaction between the 4f moments in GdZn proceeds predominantly via d‐electron polarization, whereas the RKKY‐type interaction, mediated by s electrons, is relatively weak.