Improvement of magnetic properties of CoCuPt L11 thin film by Pt(111) underlayer on glass substrate

Rhombohedral L11 type CoCuPt superstructure thin film with different thickness (t) were prepared on glass, Pt(111)/glass, and MgO(111) substrates. Soft magnetic property was obtained in CoCuPt/glass. When the film was deposited on MgO(111) substrate, the Hc is 2.2 kOe as t = 50 nm, and then it decreased to 0.65 kOe with reducing the t to 10 nm. This result is opposite of the properties in CoCuPt/Pt/glass. When the MgO(111) substrate was replaced by Pt/glass, the Hc is increased from 1.7 kOe to 2.7 kOe as the t is reduced from 50 nm to 4 nm. The nucleation field (Hn) of CoCuPt/Pt bilayer becomes more negative in thinner t indicated stronger impendence force for domain wall motion. The improvement of Hc in CoCuPt/Pt bilayer was attributed to smaller lattice mismatch at CoCuPt/Pt interface and the grain boundary pinning for domain wall motion. This suggested that magnetic properties of L11 CoCuPt films might be well controlled by adjusting the microstructure.