title: Ultrathin W space layer-enabled thermal stability enhancement in a perpendicular MgO/CoFeB/W/CoFeB/MgO recording frame.
abstract: Perpendicularly magnetized tunnel junctions (p-MTJs) show promise as reliable candidates for next-generation memory due to their outstanding features. However, several key challenges remain that affect CoFeB/MgO-based p-MTJ performance. One significant issue is the low thermal stability (Δ) due to the rapid perpendicular magnetic anisotropy (PMA) degradation during annealing at temperatures greater than 300 °C. Thus, the ability to provide thermally robust PMA characteristics is a key steps towards extending the use of these materials. Here, we examine the influence of a W spacer on double MgO/CoFeB/W/CoFeB/MgO frames as a generic alternative layer to ensure thermally-robust PMAs at temperatures up to 425 °C. The thickness-dependent magnetic features of the W layer were evaluated at various annealing temperatures to confirm the presence of strong ferromagnetic interlayer coupling at an optimized 0.55 nm W spacer thickness. Using this W layer we achieved a higher Δ of 78 for an approximately circular 20 nm diameter free layer device.
authors.affiliation: Division of Nano-Scale Semiconductor Engineering, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Jae-Hong
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Reserach Institute for Convergence of Basic Science, Novel Functional Materials and Devices Lab, Department of Physics, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Ja-Bin
authors.initials: JB
authors.lastname: Lee
authors.affiliation: Reserach Institute for Convergence of Basic Science, Novel Functional Materials and Devices Lab, Department of Physics, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Gwang-Guk
authors.initials: GG
authors.lastname: An
authors.affiliation: Reserach Institute for Convergence of Basic Science, Novel Functional Materials and Devices Lab, Department of Physics, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Seung-Mo
authors.initials: SM
authors.lastname: Yang
authors.affiliation: Nano Quantum Electronics Lab, Department of Electronics and Computer Engineering, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Woo-Seong
authors.initials: WS
authors.lastname: Chung
authors.affiliation: Reserach Institute for Convergence of Basic Science, Novel Functional Materials and Devices Lab, Department of Physics, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Hae-Soo
authors.initials: HS
authors.lastname: Park
authors.affiliation: Division of Nano-Scale Semiconductor Engineering, Hanyang University, Seoul 133-791, South Korea.|Reserach Institute for Convergence of Basic Science, Novel Functional Materials and Devices Lab, Department of Physics, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Jin-Pyo
authors.initials: JP
authors.lastname: Hong