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

The magnetic behavior of the bordering Ni and Cu monolayers at the interfaceof ultrathin Cu films on Ni(111) has been investigated. 111 In probes have been used, utilizing perturbed γγ 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