Magnetic properties of ultrathin Co/Ni/Pt(111) films

Magneto-optical (MO) and structural properties of ultrathin 1 monolayer (ML) Co/1 ML Ni/Pt(111) film were investigated upon thermal annealing. The change of Kerr rotation (θ K ) in polar configuration is correlated to rich phase transitions of Co-Ni intermixing and alloy formations of Co-Pt and Ni-Pt. After 830 K annealing, the film shows low-temperature saturation magnetization with Pt-rich Co-Pt alloys confined in surface upper layers and Ni-Pt alloys distributed in deeper layers. We observed that the magnetic order of Co-Pt was affected by Ni-Pt.