Magnetic Hyperfine Fields at Se Adatoms on Ni Surfaces

Magnetic hyperfine fields for Se on Ni(111) and Ni(001) surfaces were measured with the perturbed angular correlation technique. The results are $|B_{\mathrm{hf}}|=2.7\mathrm{}\left(3\right)$ T for Se on Ni(111) and $|B_{\mathrm{hf}}|=0.8\mathrm{}\left(3\right)$ T for Se on Ni(001) at 90 K. These values of magnetic hyperfine fields of an adatom deviate drastically from the known bulk value of $B_{\mathrm{hf}}=15\mathrm{}\mathrm{T}$. The surface site positions of the probe atoms are discussed with the aid of the results for the electric hyperfine interactions measured simultaneously.