Improvement of the interfacial Dzyaloshinskii-Moriya interaction by introducing a Ta buffer layer

• Published in: Applied physics letters Vol. 107; no. 14
• Main Authors: Kim, Nam-Hui, Han, Dong-Soo, Jung, Jinyong, Cho, Jaehun, Kim, June-Seo, Swagten, Henk J. M., You, Chun-Yeol
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 05-10-2015
• Subjects: ANISOTROPY; Applied physics; Buffer layers; BUFFERS; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Cobalt; ENERGY DENSITY; Ferromagnetism; Flux density; Frequency shift; HEAVY METALS; INTERFACES; LAYERS; LIGHT SCATTERING; Magnetic anisotropy; Magnetic saturation; MAGNETIZATION; MATERIALS; SATURATION; SPIN WAVES; TANTALUM; THICKNESS
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4932550

We report systematic measurements of the interfacial Dzyaloshinskii-Moriya interaction (iDMI) by employing Brillouin light scattering in Pt/Co/AlOx and Ta/Pt/Co/AlOx structures. By introducing a tantalum buffer layer, the saturation magnetization and the interfacial perpendicular magnetic anisotropy are significantly improved due to the better interface between heavy metal and ferromagnetic layer. From the frequency shift between Stokes- and anti-Stokes spin-waves, we successively obtain considerably larger iDM energy densities (Dmax = 1.65 ± 0.13 mJ/m2 at tCo = 1.35 nm) upon adding the Ta buffer layer, despite the nominally identical interface materials. Moreover, the energy density shows an inverse proportionality with the Co layer thickness, which is the critical clue that the observed iDMI is indeed originating from the interface between the Pt and Co layers.