Thermally robust perpendicular Co/Pd-based synthetic antiferromagnetic coupling enabled by a W capping or buffer layer

• Published in: Scientific reports 2016-02, Vol.6 (1), p.21324-21324, Article 21324
• Main Authors: Lee, Ja-Bin, An, Gwang-Guk, Yang, Seung-Mo, Park, Hae-Soo, Chung, Woo-Seong, Hong, Jin-Pyo
• Format: Article
• Language: English
• Subjects: 639/301/1005/1008; 639/301/357/997; Anisotropy; Annealing; Electrons; High temperature; Humanities and Social Sciences; multidisciplinary; Science; Structural analysis; Temperature effects
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep21324

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.