We investigate the dependence of magnetic properties of MgO/CoFeB/Ta stacks on thicknesses of CoFeB ranging from 2 to 30 nm and Ta from 1 to 10nm before and after annealing at 300-400 °C for 1-3 h. The annealing increases the saturation magnetic moment per unit area and reduces the magnitude of the damping constant in CoFeB. The annealing effect becomes smaller with increasing CoFeB thickness and with decreasing Ta thickness, indicating that the effect is related to B diffusion from CoFeB to Ta. We show that the amount of diffused B can be controlled by Ta layer thickness and annealing duration.
ASJC Scopus subject areas
- Physics and Astronomy(all)