Magnetic Anisotropy Energy of L1₀ CoPt-B Thin Films Elongated c-axis

Abstract

Very small amount of B promotes the disorder/order transformation of L1₀ CoPt at low annealing temperature along with excellent c-axis orientation. The c-axis is slightly expanded by B atoms interstitially incorporated into the octahedral sites in the L1₀ CoPt lattice. Magnetic measurements using Hall magnetometry have revealed that the magnetic anisotropy energy (MAE) is enhanced by elongation of the c-axis. This result is in harmony with the first principles calculation which predicts that the c-axis elongation enhances the MAE of L1₀ CoPt due to the d band splitting of Co near the Fermi level in the minority spin state.