Role of top and bottom interfaces of a Pt/Co/AlOx system in Dzyaloshinskii-Moriya interaction, interface perpendicular magnetic anisotropy, and magneto-optical Kerr effect

• Published in: AIP advances Vol. 7; no. 3; pp. 035213 - 035213-9
• Main Authors: Kim, Nam-Hui, Cho, Jaehun, Jung, Jinyong, Han, Dong-Soo, Yin, Yuxiang, Kim, June-Seo, Swagten, Henk J. M., Lee, Kyujoon, Jung, Myung-Hwa, You, Chun-Yeol
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 01-03-2017; AIP Publishing LLC
• Subjects: Cobalt; Flux density; Insertion; Kerr effects; Kerr magnetooptical effect; Magnetic anisotropy; Thickness; Thin films
• ISSN: 2158-3226; 2158-3226
• DOI: 10.1063/1.4978867

We investigate the role of top and bottom interfaces in inversion symmetry-breaking Pt/Co/AlOx systems by inserting ultra-thin Cu layers. Wedge-type ultrathin Cu layers (0-0.5 nm) are introduced between Pt/Co or Co/AlOx interfaces. Interface sensitive physical quantities such as the interfacial Dzyaloshinskii-Moriya interaction (iDMI) energy density, the interfacial perpendicular magnetic anisotropy (iPMA), and the magneto-optical Kerr effects (MOKE) are systematically measured as a function of Cu-insertion layer thickness. We find that the Cu-insertion layer in the bottom interface (Pt/Co) plays a more important role in iDMI, PMA, and MOKE. In contrast, the top interface (Co/AlOx) noticeably contributes to only PMA, while its contributions to iDMI and MOKE enhancement are less significant. Although the PMA mainly comes from the bottom interface (Pt/Co), the Cu-insertion layers of all interfaces (Pt/Co, Co/AlOx) influence PMA. For iDMI, only the Cu-insertion layer in the bottom interface exerts SOC suppression which leads iDMI energy to decrease rapidly.