@article{e7028a878f9544fc8a9b0e7eb96629cf,
title = "TaFeB spacer for soft magnetic composite free layer in CoFeB/MgO/CoFeB-based magnetic tunnel junction",
abstract = "CoFeB/MgO/CoFeB-based magnetic tunnel junctions (MTJs) with a soft magnetic composite free layer have been developed for magnetic sensor applications. Tunnel magnetoresistance (TMR) ratios in the sensor-type MTJs have reached a ceiling due to a trade-off between the TMR ratio and interlayer exchange coupling (IEC) depending on the spacer thickness of the composite free layer. In this study, we developed a paramagnetic amorphous TaFeB-alloy spacer to replace the conventional Ta spacer and solve this trade-off. The TaFeB film showed a wider thickness window for a sufficient IEC, resulting in IEC energy values of 0.18-0.19 erg/cm2 at a thickness of 1.0 nm. In addition, we confirmed that the TaFeB film had an ability to function as a boron sink comparable to that of pure Ta. These characteristics allowed us to thicken the TaFeB spacer up to 1.0 nm in the sensor-type MTJs and attain an enhanced TMR ratio of up to 234%, which is the highest compared with cases using the conventional Ta spacer reported to date. These findings demonstrate that TaFeB alloy is a promising material for breaking the ceiling of sensor-type MTJs and increasing sensitivity.",
author = "Takafumi Nakano and Kosuke Fujiwara and Seiji Kumagai and Yasuo Ando and Mikihiko Oogane",
note = "Funding Information: This work was based on the results obtained from a project, JPNP14004, subsidized by the New Energy and Industrial Technology Development Organization (NEDO). This work was, in part, supported by the Center for Science and Innovation in Spintronics (CSIS) and the Center for Innovative Integrated Electronic System (CIES). The authors would like to thank M. Al-Mahdawi for his assistance in the free energy calculation, and S. Mizukami for his assistance in the TMR measurement by the current in-plane tunneling method. Funding Information: This work was based on the results obtained from a project, JPNP14004, subsidized by the New Energy and Industrial Technology Development Organization (NEDO). This work was, in part, supported by the Center for Science and Innovation in Spintronics (CSIS) and the Center for Innovative Integrated Electronic System (CIES). The authors would like to thank M. Al-Mahdawi for his assistance in the free energy calculation, and S. Mizukami for his assistance in the TMR measurement by the current in-plane tunneling method. Publisher Copyright: {\textcopyright} 2023 Author(s).",
year = "2023",
month = feb,
day = "13",
doi = "10.1063/5.0132866",
language = "English",
volume = "122",
journal = "Applied Physics Letters",
issn = "0003-6951",
publisher = "American Institute of Physics Publising LLC",
number = "7",
}