Magnetic vortex racetrack memory

Abstract

We report a new type of racetrack memory based on current-controlled movement of magnetic vortices in magnetic nanowires with rectangular cross-section and weak perpendicular anisotropy. Data are stored through the core polarity of vortices and each vortex carries a data bit. Besides high density, non-volatility, fast data access, and low power as offered by domain wall racetrack memory, magnetic vortex racetrack memory has additional advantages of no need for constrictions to define data bits, changeable information density, adjustable current magnitude for data propagation, and versatile means of ultrafast vortex core switching. By using micromagnetic simulations, current-controlled motion of magnetic vortices in cobalt nanowire is demonstrated for racetrack memory applications.

Commensurate vortex-core switching in magnetic nanodisks at gigahertz frequencies

“…In recent years, several applications have been proposed whose operation relies on the magnetization dynamics in nanostructures, ranging from nonvolatile memory devices [1][2][3][4][5] to logic devices [6][7][8][9][10], over spin-wave based communication and information processing devices [11][12][13]. It is therefore of fundamental importance to understand the magnetization dynamics in such structures, e.g., magnetic nanodisks in which the vortex state appears due to the competition between the short-range exchange interaction and the long-range magnetostatic interaction.…”

“…Mechanisms to reverse the circulation and core polarization in a reliable, fast, and energetically efficient manner have been studied because of their importance in the development of vortex-based memory [2,5] and logic [16,17] devices. In order to change the circulation, the original vortex core is expelled from the disk by applying an in-plane magnetic field, * bartel.vanwaeyenberge@ugent.be after which a new core can nucleate at the border [18][19][20].…”

Cycloidal Domains in the Magnetization Reversal Process of Ni80Fe20/Nd16Co84/Gd12CoQuirós1, Hierro-Rodríguez2, Sorrentino3 et al. 2018Phys. Rev. Applied5060View full textAdd to dashboardCite

“…In particular, magnetic vortex-antivortex nucleation is determined by topological characteristics (polarity, chirality, and bifurcation geometry) [11,14], resulting in a robust mechanism to control the propagation of vortices and antivortices at top and bottom sample surfaces. Applications of this effect into memory devices based on the concept of magnetic vortex racetracks [15][16][17] would require a broad enough field range in which vortex motion can be reversibly controlled by an applied magnetic field and is effectively guided by the stripe-domain pattern. These issues require a detailed characterization of the field-dependent domain configuration of WPMA multilayers when vortex-antivortex pairs are present in the system.…”

Simulation and Modeling of Racetrack Memories With VCMA Synchronization

“…Among the magnetic domain synchronization techniques, the notch technology is of relevant prominence: the magnetic track is lithographically modified and pinning sites, suitable for the synchronization of domain walls, are realized. In the literature, the confinement of domain walls in magnetic nanowires by the use of lithographic notch has been deeply investigated in [1], [5], [6]. In this article, we explore the Voltage-Controlled Magnetic Anisotropy (VCMA) [7] effect as a synchronization method for racetrack memory and domain wall logic technology.…”