Antiferromagnet-induced perpendicular magnetic anisotropy in ferromagnetic/antiferromagnetic/ferromagnetic trilayers

This study demonstrates the effect of antiferromagnet-induced perpendicular magnetic anisotropy (PMA) on ferromagnetic/antiferromagnetic/ferromagnetic (FM/AFM/FM) trilayers and reveals its interplay with a long-range interlayer coupling between separated FM layers. In epitaxially grown 12 monolayer (ML) Ni/Co/Mn/5 ML Co/Cu(001) films, magnetic hysteresis loops and element-resolved magnetic domain imaging showed that the magnetization direction of the top layers of 12 ML Ni/Co films could be changed from the in-plane direction to the perpendicular direction, when the thickness of the Mn films (${\mathrm{t}}_{\mathrm{Mn}}$) was greater than a critical value close to the thickness threshold associated with the onset of AFM ordering (${\mathrm{t}}_{\mathrm{Mn}}=3.5$ ML). The top FM layers exhibited a significantly enhanced PMA when ${\mathrm{t}}_{\mathrm{Mn}}$ increased further, and this enhancement can be attributed to a strengthened AFM ordering of the volume moments of the Mn films, as evidenced by the presence of induced domain frustration. By contrast, the long-range interlayer coupling presented clear effects only when ${\mathrm{t}}_{\mathrm{Mn}}$ was at a lower coverage.