Effect of oxygen incorporation on dynamic magnetic properties in Ta-O/Co-Fe-B bilayer films under out-of-plane and in-plane magnetic fields

Dynamic magnetic properties of Ta-O/Co20Fe60B20 bilayer films are strongly influenced by the oxidation condition of the Ta-O layer. The oxidation of the Ta-O layer by a slight amount of oxygen with a pressure (P-Oxygen) of 0.03 Pa decreases in-plane damping constant (alpha(IP)), and increases the effective magnetization (4 pi M-s,M-eff). Then, both alpha(IP) and 4 pi M-s,M-eff maintain their values by increasing P-Oxygen up to 0.3 Pa. The out-of-plane damping constant (alpha(OP)) showed a similar tendency to that of alpha(IP) against P-Oxygen, although alpha(OP) is much smaller than alpha(IP) in every P-Oxygen. alpha(OP) reaches to 0.0033 for sample oxidized at 0.03 Pa. It was suggested that alpha(IP) consists of both the intrinsic damping and the extrinsic damping, while alpha(OP) is closer to the intrinsic damping. The control of alpha(OP) and alpha(IP) by the oxidation would be beneficial in designing the high frequency spintronic devices. (c) 2022 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). https://doi.org/10.1063/9.0000297

Automated summary

The dynamic magnetic properties of Ta-O/Co20Fe60B20 bilayer films are greatly influenced by the oxidation condition of the Ta-O layer. The oxidation of the Ta-O layer leads to a decrease in the in-plane damping constant and an increase in the effective magnetization. The out-of-plane damping constant shows a similar trend but with a much smaller magnitude compared to the in-plane damping constant.