Perpendicular magnetic clusters with configurable domain structures via dipole-dipole interactions

• Published in: Nano research Vol. 8; no. 11; pp. 3639 - 3650
• Main Authors: Li, Weimin, Wong, Seng Kai, Herng, Tun Seng, Yap, Lee Koon, Sim, Cheow Hin, Yang, Zhengchun, Chen, Yunjie, Shi, Jianzhong, Han, Guchang, Xue, Junmin, Ding, Jun
• Format: Journal Article
• Language: English
• Published: Beijing Tsinghua University Press 01.11.2015; Springer Nature B.V
• Subjects: Anisotropy; Atomic/Molecular Structure and Spectra; Biomedicine; Biotechnology; Chemistry and Materials Science; Clusters; Cobalt; Condensed Matter Physics; Dipole interactions; Dipoles; Electron beam lithography; Fluctuations; Flux; Islands; Landau; Magnetic fields; Magnetic properties; Magnetic recording; Magnetic saturation; Magnetization; Materials Science; Multilayers; Nanotechnology; Palladium; Programmable logic devices; Research Article; Saturation (magnetic); Spintronics; 偶极-偶极相互作用; 可编程逻辑器件; 可配置; 垂直各向异性; 形状各向异性; 结构域; 饱和磁化强度; dipole–dipole interaction; logic device; multistate magnetic recording; magnetic domino; perpendicular anisotropy
• ISSN: 1998-0124; 1998-0000
• DOI: 10.1007/s12274-015-0864-1

Magnetic single-domain islands based on in-plane anisotropy （usually, shape anisotropy） and their dipole-dipole interactions have been investigated extensively in recent years. This has been driven by potential applications in magnetic recording, spintronics, magneto-biology, etc. Here, we propose a concept of out- of-plane magnetic dusters with configurable domain structures （multi-flux states） via dipole-dipole interactions. Their flux stages can be switched through an external magnetic field. The concept has been successfully demonstrated by patterned [Co/Pd] islands. A [Co/Pd] multilayer exhibits a large perpendicular anisotropy, a strong physical separation, and uniform intrinsic properties after being patterned into individual islands by electron beam lithography. A three- island cluster with six stable flux states has been realized by optimizing island size, thickness, gap, anisotropy, saturation magnetization, etc. Using [Co/Pd] multilayers, we have optimized the island structure by tuning magnetic properties （saturation magnetization and perpendicular anisotropy） using Landau-Liftshitz- Gilbert （LLG） simulation/calculation. Potential applications have been proposed, including a flexi-programmable logic device with AND, OR, NAND, and NOR functionalities and a magnetic domino, which can propagate magnetic current as far as 1 μm down from the surface via vertical dipole-dipole interactions.