title: Thermally robust perpendicular Co/Pd-based synthetic antiferromagnetic coupling enabled by a W capping or buffer layer.
abstract: Perpendicularly magnetized tunnel junctions (p-MTJs) that contain synthetic antiferromagnetic (SAF) frames show promise as reliable building blocks to meet the demands of perpendicular magnetic anisotropy (PMA)-based spintronic devices. In particular, Co/Pd multilayer-based SAFs have been widely employed due to their outstanding PMA features. However, the widespread utilization of Co/Pd multilayer SAFs coupled with an adjacent CoFeB reference layer (RL) is still a challenge due to the structural discontinuity or intermixing that occurs during high temperature annealing. Thus, we address the thermally robust characteristics of Co/Pd multilayer SAFs by controlling a W layer as a potential buffer or capping layer. The W-capped Co/Pd multilayer SAF, which acts as a pinning layer, exhibited a wide-range plateau with sharp spin-flip and near-zero remanence at the zero field. Structural analysis of the W-capped multilayer SAF exhibited single-crystal-like c-axis oriented crystalline features after annealing at 400 °C, thereby demonstrating the applicability of these frames. In addition, when the W layer serving as a buffer layer in the Co/Pd multilayer SAF was coupled with a conventional CoFeB RL, higher annealing stability up to 425 °C and prominent antiferromagnetic coupling behavior were obtained.
authors.affiliation: Novel Functional Materials and Device Lab., Research Institute of Convergence of Basic Science, Department of Physics, Hanyang University, Seoul, 133-791, South Korea.
authors.forename: Ja-Bin
authors.initials: JB
authors.lastname: Lee
authors.affiliation: Novel Functional Materials and Device Lab., Research Institute of Convergence of Basic Science, Department of Physics, Hanyang University, Seoul, 133-791, South Korea.
authors.forename: Gwang-Guk
authors.initials: GG
authors.lastname: An
authors.affiliation: Novel Functional Materials and Device Lab., Research Institute of Convergence of Basic Science, Department of Physics, Hanyang University, Seoul, 133-791, South Korea.
authors.forename: Seung-Mo
authors.initials: SM
authors.lastname: Yang
authors.affiliation: Novel Functional Materials and Device Lab., Research Institute of Convergence of Basic Science, Department of Physics, Hanyang University, Seoul, 133-791, South Korea.
authors.forename: Hae-Soo
authors.initials: HS
authors.lastname: Park
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: Novel Functional Materials and Device Lab., Research Institute of Convergence of Basic Science, Department of Physics, Hanyang University, Seoul, 133-791, South Korea.
authors.forename: Jin-Pyo
authors.initials: JP
authors.lastname: Hong