Domain wall in (FeCo)–Zr–O thin film profiled by spin-polarized scanning tunneling microscopy

The domain structure of (FeCo)–Zr–O thin film was observed with spin-polarized scanning tunneling microscopy. A maze domain is characterized by a domain width of about 320 nm, and a wall energy of 4.97 erg cm−2. The tunneling magnetoresistance (TMR) profile is fitted by a tanh function, and a wall thickness of about 100 nm is obtained. This indicates that the TMR is proportional to the angle between the tip and the film magnetizations. Effective exchange and anisotropy constants are estimated at 3.88 × 10−6 erg cm−1 and 3.98 × 105 erg cm−3, respectively.