Monolayer-resolved detection of magnetic hyperfine fields at Cu/Ni(111) interfaces

The magnetic behavior of the bordering Ni and Cu monolayers at the interface of ultrathin Cu films on Ni(111) has been investigated. ¹¹¹In probes have been used, utilizing perturbed {γ}{γ} angular correlations, to study strength, orientation, and temperature dependence of the magnetic hyperfine field at the probe nuclear site. This magnetic hyperfine field is strongly reduced to about 50% in the first Ni layer covered by Cu; it vanishes in the adjacent Cu layer. The results are compared to hyperfine fields at free Ni(111) surfaces, to magnetometry measurements, and to theoretical predictions.