Thermal Annealing Effects on the Interfacial Dzyaloshinskii-Moriya Interaction Energy Density and Perpendicular Magnetic Anisotropy

We investigate the interfacial Dzyaloshinskii-Moriya interaction (iDMI) and the perpendicular magnetic anisotropy (PMA) in the annealed inversion symmetry breaking structures (Pt/Co (CoFeB)/AlO_x and Ta/CoFeB/AlO_x) by Brillouin light scattering. The iDMI energy density of Pt/Co and Pt/CoFeB samples decreases while increasing annealing temperature, but the iDMI energy density of Ta/CoFeB sample slightly increases by increasing annealing temperature. By applying the thermal annealing process, PMA energies slightly increase at the Pt/Co interface; however, Pt/CoFeB, (Ta/CoFeB) structures are dramatically decreased (increased) by the annealing process. The effects of the annealing show complicate variation for iDMI and PMA for each structure; however, we find overall weak correlations between iDMI and PMA despite different materials and annealing process.