Growth of L11 structured CoPt thin films by alternate sputtering method on glass substrate

•Recently identified metastable superlattice of CoPt with strong perpendicular magnetic anisotropy•Prepared L11 CoPt thin film with multilayer structure•Growth of L11 structured CoPt thin films by alternate sputtering method•Well controllable magnetic properties of L11 CoPt films by adjusting the thickness of individual Co and Pt layer

L11 structured [Cox/Ptx]n multilayer films (x = 0.1–2 nm and n = 1–20) were prepared by alternate sputtering of Co and Pt layers on glass substrate with textured Pt(111) underlayer. The [Cox/Ptx]n multilayer films showed higher perpendicular magnetic anisotropy (PMA) and out-of-plane coercivity (Hc ⊥) for x = 0.3–0.5 and n = 4–6. Poor PMA was found when x was below 0.3. Further increase in x and n, the magnetic properties of [Co/Pt]n multilayer films significantly deteriorated. In this study, [Co0.5/Pt0.5]4 multilayer film showed high PMA, high magnetocrystalline anisotropy constant (Ku ~ 2.1 × 106 J/m3), and larger Hc ⊥ (~ 160 kA/m). It is demonstrated that L11 structured [Cox/Ptx]n multilayer films with better perpendicular magnetic properties can be fabricated by alternate sputtering method. The correlation between magnetic properties and microstructures of [Cox/Ptx]n multilayer films with different x and n was also investigated.