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.