CoFeB/MgO/CoFeB magnetic tunnel junctions prepared by layer-by-layer growth of naturally oxidized MgO. (9th September 2019)

• Record Type: Journal Article
• Authors: Konoto, Makoto; Murayama, Akiyuki; Ochiai, Takao; Amano, Minoru; Yakushiji, Kay; Kubota, Hitoshi; Yuasa, Shinji
• Is Part Of: Applied physics express. Volume 12:Number 10(2019)
• Publication Date: 2019-09-09
• Subjects: Physics -- Periodicals; Technology -- Periodicals; 621.05
• DOI: 10.7567/1882-0786/ab3e55
• Languages: English
• ISSNs: 1882-0778

Abstract

Abstract: We fabricated CoFeB/MgO/CoFeB magnetic tunnel junctions (MTJs) by naturally oxidizing dc-sputtered Mg and investigated the formation process of MgO(001) by reflective high-energy diffraction. The 0.26 nm thick Mg layer on amorphous CoFe(B) had an amorphous structure in the as-deposited state and a monolayer (ML) of textured MgO(001) formed by natural oxidation. By repeating the deposition/oxidation of 0.26 nm thick Mg layers, a highly textured MgO(001) barrier layer was prepared. Surprisingly, (001)-oriented crystallization was confirmed even for 2 ML thick MgO. The MTJs prepared by layer-by-layer growth of naturally oxidized MgO exhibited high MR ratios (up to 200%) and low resistance-area products suited for device applications.