Domain-wall dynamics in magnetoelastic nanostripes (original) (raw)
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Manipulation of magnetic domain wall in magnetoelastic nanostripes
2017
The motion of domain walls is typically induced by external magnetic fields or spin-polarized currents. However, concerns about energy consumption of these systems motivates the search for alternatives. Thus, there is a growing interest in the different coupling allowing the use of electric fields instead of currents to trigger domain wall motion. Among these potential solutions, magnetoelectric materials mediated by mechanical stress appear promising. Since a uniform stress alone cannot induce unidirectional domain wall motion, the symmetry breaking of the stable states of a nanomagnet allows for a simpler implementation of the mechanical coupling. This can be achieved by a transverse magnetic field. In a two-domain system, the stress will then provoke the expansion of one of them at the expense of the other, which causes domain wall motion. Here, we propose a description of the peculiar characteristics of 23ème Congrès Français de Mécanique Lille, 28 au 1er Septembre 2017 domain w...
Mechanically driven domain wall movement in magnetoelastic nanomagnets
The European Physical Journal B, 2016
Magnetic domain walls are fundamental objects arising in ferromagnetic materials, largely investigated both through micromagnetic simulations and experiments. While current-and field-based techniques for inducing domain wall propagation have been widely studied for fundamental understanding and application-oriented purposes, the possibility to manipulate domain walls using mechanical stress in magnetoelastic materials has only recently drawn interest. Here, a complete analytical model describing stress-induced transverse domain wall movement in ferromagnetic nanostripe with variable cross-section is presented. This approach yields a nonlinear integro-differential equation describing the magnetization field. Its numerical implementation, based on the nonlinear relaxation method, demonstrates the possibility to precisely control the position of a domain wall through mechanical action.
Applied Mathematical Modelling, 2020
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Domain Wall Motion in Magnetic Nanostrips
Materials Science and Technology, 2020
Domain walls are the transition regions between two magnetic domains. These objects have been very relevant during the last decade, not only due to their intrinsic interest in the development of novel spintronics devices but also because of their fundamental interest. The study of domain wall has been linked to the research on novel spin-orbit coupling phenomena such as the Dzyaloshinskii-Moriya interaction and the spin Hall effect amount others. Domain walls can be nucleated in ferromagnetic nanostrips and can be driven by conventional magnetic fields and spin currents due to the injection of electrical pulses, which make them very promising for technological applications of recording and logic devices. In this review, based on full micromagnetic simulations supported by extended one-dimensional models, we describe the static and dynamic properties of domain walls in thin ferromagnetic and ferrimagnetic wires with perpendicular magnetic anisotropy. The present chapter aims to provide a fundamental theoretical description of the fundaments of domain walls, and the numerical tools and models which allow describing the DW dynamics in previous and future experimental setups.
Physical Review Letters, 2012
Domain wall motion induced by nanosecond current pulses in nanostripes with perpendicular magnetic anisotropy (Pt/Co/AlOx) is shown to exhibit negligible inertia. Time-resolved magnetic microscopy during current pulses reveals that the domain walls start moving, with a constant speed, as soon as the current reaches a constant amplitude, and no or little motion takes place after the end of the pulse. The very low 'mass' of these domain walls is attributed to the combination of their narrow width and high damping parameter α. Such a small inertia should allow accurate control of domain wall motion, by tuning the duration and amplitude of the current pulses.
Dynamics of Domain Walls in Magnetic Nanostrips
Physical Review Letters, 2008
We express dynamics of domain walls in ferromagnetic nanowires in terms of collective coordinates generalizing Thiele's steady-state results. For weak external perturbations the dynamics is dominated by a few soft modes. The general approach is illustrated on the example of a vortex wall relevant to recent experiments with flat nanowires. A two-mode approximation gives a quantitatively accurate description of both the steady viscous motion of the wall in weak magnetic fields and its oscillatory behavior in moderately high fields above the Walker breakdown.
Metastable magnetic domain wall dynamics
New Journal of Physics, 2012
The dynamics of metastable magnetic domain walls in straight ferromagnetic nanowires under spin waves, external magnetic fields, and current induced spin transfer torque are studied by micromagnetic simulations. It is found that in contrast to a stable wall, it is possible to displace a metastable domain wall in the absence of any external excitation. In addition, independent of the domain wall excitation method, the velocity of a metastable wall is much smaller than a stable wall and their displacement direction could be different from the stable wall depending on the structure of metastable walls. Under the current induced spin transfer torque excitation, the direction of domain wall displacement is directly related to the intensity of nonadiabatic spin transfer torque. In a rough nanowire, it is found that the displacement of a metastable wall could happen much below the critical excitation of a stable wall. Furthermore, we show that it is possible to have either a forward or backward displacement of a metastable domain wall by changing the pulse width of the excitation.
Dynamic transformations of the internal structure of a moving domain wall in magnetic nanostripes
Physical Review B, 2007
The magnetic field (or electric current) driven domain-wall motion in magnetic nanostripes is of considerable interest because it is essential to the performance of information storage and logic devices. One of the currently key problems is to unveil the complex behaviors of oscillatory domain-wall motions under applied magnetic fields stronger than the so-called Walker field, beyond which the velocity of domain walls markedly drops. Here, we provide not only considerably better understandings but also new details of the complex domainwall motions. In a certain range just above the Walker field, the motions are not chaotic but rather periodic with different unique periodicities of dynamic transformations of a moving domain wall between the different types of its internal structure. Three unique periodicities found, which consist of different types of domain wall that are transformed from type one to another. The transformation periods vary with the field strength and the nanostripe width.
Applied Physics Letters, 2016
The motion of a ferromagnetic domain wall in nanodevices is usually induced by means of external magnetic fields or polarized currents. Here, we demonstrate the possibility to reversibly control the position of a N eel domain wall in a ferromagnetic nanostripe through a uniform mechanical stress. The latter is generated by an electro-active substrate combined with the nanostripe in a multiferroic heterostructure. We develop a model describing the magnetization distribution in the ferromagnetic material, properly taking into account the magnetoelectric coupling. Through its numerical implementation, we obtain the relationship between the electric field applied to the piezoelectric substrate and the position of the magnetic domain wall in the nanostripe. As an example, we analyze a structure composed of a PMN-PT substrate and a TbCo 2 /FeCo composite nanostripe.