Anomalous Hall effect in Co/Ni multilayers with perpendicular magnetic anisotropy

Anomalous Hall effect is studied in Co/Ni multilayers with perpendicular magnetic anisotropy, which consists of ferromagnetic-ferromagnetic interfaces. The anomalous Hall coefficient of [Co/Ni]N multilayer increases with temperature. The anomalous Hall coefficient at the zero temperature limit is in the order of 0.01 μΩ cm/T and decreases with increasing the repetition N. It suggests that the Co-Ni interfacial contribution to anomalous Hall coefficient is of opposite sign to the bulk contribution. The anomalous Hall coefficient increases linearly with the resistivity of the Co/Ni multilayer, indicating the scattering may play a dominant role on the anomalous Hall effect.