The magnetic properties of Co80 Pt20 (10 nm) Co (0,3,5 nm) hard/soft stacked dot arrays with dot diameters D of about 50 nm were studied. Co-Pt films were deposited on Ru (001) seed layers, resulting in a large uniaxial magnetic anisotropy Ku with the c axis perpendicular to the film plane. Dot patterns were formed using high resolution e-beam lithography and reactive ion etching. Magnetic force microscopy images revealed that all dot arrays showed a single domain state, even after removal of an applied field equal to the coercivity. The remanence coercivity Hr decreased from 9.1 to 6.9 kOe as the Co layer thickness increased from 0 to 5 nm, indicating that the hard/soft stacked structure was effective at reducing the switching field, as theoretically predicted. The applied field angular dependence of Hr for 10-nm -thick Co-Pt dot arrays was in good agreement with calculations based on the Stoner-Wohlfarth model, HS-W indicating coherent rotation of the magnetization during nucleation. Moreover, it was confirmed that the hard/soft stacked structure reduced the angular variation of Hr.
ASJC Scopus subject areas
- Physics and Astronomy(all)