Oscillatory interlayer coupling in Co/Pt multilayers with perpendicular anisotropy

Interlayer coupling in several series of [Co/Pt](N) multilayers with perpendicular anisotropy and Pt thicknesses from 3 to 79 angstrom has been investigated using magnetometry measurements at temperatures from 293 K down to 8 K. Oscillatory interlayer coupling with a ferromagnetic background as a function of the Pt thickness was observed in every multilayer series. This oscillation of interlayer coupling can be attributed to the Ruderman-Kittel-Kasuya-Yosida interaction. Unusual temperature dependence of the coercivity and the saturation magnetization suggests that the polarization of Pt atoms by the adjacent Co layers is responsible for the ferromagnetic interlayer coupling in Co/Pt multilayers and the magnetic polarization of Pt atoms extends further into the Pt layers as the temperature decreases.