Radiation impact of swift heavy ion beams on double-interface CoFeB/MgO magnetic tunnel junctions
Bi Wang, Zhaohao Wang, Ao Du, You Qiang, Kaihua Cao, Yuanfu Zhao, Hongchao Zheng, Shaohua Yan, Pengfei Zhai, Jie Liu, Gang Guo, Yumeng Bai, Jun Wang, Weisheng Zhao
Abstract
A double-interface CoFeB/MgO magnetic tunnel junction (MTJ) has a high thermal stability barrier (E) and high-efficiency magnetization switching with the scaling of device dimensions. However, compared to a single-interface CoFeB/MgO MTJ, its more complicated film stacks and interfaces are more vulnerable to irradiation-induced swift heavy ions. We have studied the irradiation effects of Ta/Kr ions on double-interface CoFeB/MgO MTJs. Structural and physical analyses are performed through transmission electron microscopy, energy dispersive x-ray spectroscopy, and vibrating sample magnetometry. 1907 MeV Ta-ion irradiation damages the interfaces of the double-interface MTJ, resulting in the irreversible decrease in coercivity, while 2060 MeV Kr-ion irradiation damages the bulk properties of the MTJ, leading to the decrease in saturation magnetization. However, the electronic properties of the double-interface MTJ are almost immune to Kr-ion irradiation.