CoFeB/MgO/CoFeB structures with orthogonal easy axes: perpendicular anisotropy and damping. (13th November 2017)

• Record Type: Journal Article
• Authors: Głowiński, H; Żywczak, A; Wrona, J; Krysztofik, A; Gościańska, I; Stobiecki, T; Dubowik, J
• Is Part Of: Journal of physics. Volume 29:Number 48(2017)
• Publication Date: 2017-11-13
• Subjects: ferromagnetic resonance -- perpendicular magnetic anisotropy -- magnetization precession damping; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/aa9530
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: We report on the Gilbert damping parameter α, the effective magnetization 4 π M e f f, and the asymmetry of the g -factor in bottom-CoFeB(0.93 nm)/MgO(0.90–1.25 nm)/CoFeB(1.31 nm)-top as-deposited systems. Magnetization of CoFeB layers exhibits a specific noncollinear configuration with orthogonal easy axes and with 4 π M e f f values of + 2.2 kG and − 2.3 kG for the bottom and top layers, respectively. We show that 4 π M e f f depends on the asymmetry g ⊥ − g ∥ of the g -factor measured in the perpendicular and the in-plane directions revealing a highly nonlinear relationship. In contrast, the Gilbert damping is practically the same for both layers. Annealing of the films results in collinear easy axes perpendicular to the plane for both layers. However, the linewidth is strongly increased due to enhanced inhomogeneous broadening.