Depinning of the transverse domain wall trapped at magnetic impurities patterned in planar nanowires: Control of the wall motion using low-intensity and short-duration current pulses

• Published in: Journal of magnetism and magnetic materials 2018-04, Vol.451, p.639-646
• Main Authors: Paixão, E.L.M., Toscano, D., Gomes, J.C.S., Monteiro, M.G., Sato, F., Leonel, S.A., Coura, P.Z.
• Format: Article
• Language: English
• Subjects: Anisotropy; Artificial magnetic defects; Computer simulation; Current pulses; Domain walls; Impurities; Magnetic properties; Magnetic saturation; Magnetism; Melt spinning; Micromagnetic simulations; Motion control; Nanowires; Notches; Parameters; Simulation; Spin transfer torque; Stiffness; Transverse domain wall
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2017.11.117

•Traps for pinning transverse domain walls are proposed.•The traps consisting of located modifications of the magnetic properties.•Domain wall depinning by applying low-intensity and short-duration current pulses. Understanding and controlling of domain wall motion in magnetic nanowires is extremely important for the development and production of many spintronic devices. It is well known that notches are able to pin domain walls, but their pinning potential strength are too strong and it demands high-intensity current pulses to achieve wall depinning in magnetic nanowires. However, traps of pinning can be also originated from magnetic impurities, consisting of located variations of the nanowire’s magnetic properties, such as exchange stiffness constant, saturation magnetization, anisotropy constant, damping parameter, and so on. In this work, we have performed micromagnetic simulations to investigate the depinning mechanism of a transverse domain wall (TDW) trapped at an artificial magnetic defect using spin-polarized current pulses. In order to create pinning traps, a simplified magnetic impurity model, only based on a local reduction of the exchange stiffness constant, have been considered. In order to provide a background for experimental studies, we have varied the parameter related to the pinning potential strength of the magnetic impurity. By adjusting the pinning potential of magnetic impurities and choosing simultaneously a suitable current pulse, we have found that it is possible to obtain domain wall depinning by applying low-intensity and short-duration current pulses. Furthermore, it was considered a planar magnetic nanowire containing a linear distribution of equally-spaced magnetic impurities and we have demonstrated the position control of a single TDW by applying sequential current pulses; that means the wall movement from an impurity to another.