Perpendicular magnetic anisotropy and domain structure of L1₀-ordered FePt films fabricated by monatomic layer control

Magnetic domain structures and perpendicular magnetic anisotropies for L1₀-ordered FePt alloy films have been investigated. The films were prepared by alternating Fe [001] and Pt [001] monatomic layers on MgO [001] substrates at low temperatures below 230°C. In addition to the fundamental [002] peak, [001] and [003] superlattice peaks have clearly been observed in the X-ray diffraction patterns, indicating the formation of an L1₀-ordered structure. The magnetization measurements show that all the samples are perpendicularly magnetized. Good magnetic squareness (Mr/Ms∼0.9) from the magnetization curves are obtained and highly interconnected stripe domain patterns are observed for the samples grown at Ts ≥ 160°C.