磁各向异性垂直于膜面的Co/Pt多层膜中的反铁磁层间交换耦合

By using one ultrathin NiO layer to replace the Pt capping layer in the Co/Pt multilayer with perpendicular anisotropy, we present direct evidence for the existence of antiferromagnetic interlayer coupling between the Co layers through the Pt layers thicker than 24 ? The NiO capping layers play two key roles in the observation of antiferromagnetic interlayer coupling. One is the manipulation of the coercivity of the Co layer in contact with the NiO layer, the other is the enhancement of the electron reflectivities at the Co/Pt interfaces via the specular scattering effect at the Co-NiO interface. The thermal variation of the magnetization of the Co layer also plays an important role in the observed antiferromagnetic coupling due to its strong effect on the phase of electron reflectivity at the Co/Pt interfaces. The magnetization-dependent phase can lead to the ferromagnetic-antiferromagnetic transition of the interlayer coupling at high temperature. All these factors are combined together to realize the direct observation of antiferromagnetic interlayer coupling in the Co/Pt multilayer with perpendicular anisotropy.