Effect of annealing temperature on structure and magnetic properties of L1₀-FePd/CoFeB bilayer

The effects of annealing temperature on the structural and magnetic properties of CoFeB/FePd bilayer were systematically investigated. A thin (0.5 nm) CoFeB layer was inserted between the FePd and MgO layers and then annealed at different temperatures. The magnetic anisotropy field increased with an increase in the annealing temperature owing to the enhancement of the interfacial perpendicular magnetic anisotropy (PMA) by crystallizing the thin CoFeB layer. The thermal annealing of the deposited layers promoted L1 ₀ ordering and reduced the surface roughness. It was found that a thinner FePd layer requires a higher annealing temperature in order to achieve PMA. After annealing at 350°C, a PMA of 7.1 Merg/cc was obtained even for a thin FePd film with a thickness of 2.0 nm.