Observation of magnetization reversal processes in Co–Cr and Co–Cr–Ta ultrathin films under the canted magnetic field using anomalous Hall effect

Normalized magnetization vector Me of ultrathin Co–Cr–Ta films under the canted magnetic field were derived from the results of anomalous Hall voltage and the magnetization measured by a vibrating sample magnetometer. The film deposited at high substrate temperature revealed a relatively large amount of an in-plane component because of the faint c-axis orientation in the perpendicular direction of the Co–Cr–Ta crystallites. The in-plane component at the remanent state seems to be larger for the film with worse c-axis orientation. The Pt underlayer was normalized to promote c-axis orientation in Co–Cr–Ta films deposited on it at a high substrate temperature above 200 °C. A 30 nm-thick Co77Cr20Ta3 film deposited on a 20-nm-thick Pt underlayer exhibited large perpendicular coercivity. The locus of normalized magnetization of the Co77Cr20Ta3(30 nm)/Pt(20 nm) implied that the film revealed a large perpendicular magnetization component even though the magnetic field was applied in the direction out of the normal line.