Single vortex core recording in a magnetic vortex lattice

Abstract

We investigated the reversal characteristics of magnetic vortex cores in a two dimensional assembly of magnetic vortices. The vortex lattice was created by film deposition of 30-nm-thick permalloy onto large arrays of self-assembled spherical SiO2-particles with a diameter of 330 nm. The vortex core reversal was investigated by employing a write/read tester. This device uses a state-of-the-art magnetic recording head of a hard disc drive, which allows imaging as well as applying a local magnetic field pulse to individual vortices. The successful writing and reading of individual vortex cores is demonstrated, including a switching map, which indicates the switching behavior dependent on the relative position of the field pulse with respect to the vortex core.

Stray fields above artificial magnetic in-plane domains

“…As this study should quantify magnetic fields for possible applications at room temperature, techniques requiring cryogenic temperatures like SQUID measurements are excluded. Methods fulfilling these conditions are quantitative magnetic force microscopy (qMFM) [9], nitrogen vacancy (NV) center magnetometry [10,11], scanning magnetoresistive microscopy [12] and m-Hall probe microscopy [13]. Here we present a quantitative determination of the stray field z-component (perpendicular to the sample surface) strength as a function of lateral position and height over the surface by m-Hall probe microscopy.…”

Stochastic nature of magnetic processes studied by full-field soft X-ray microscopy

“…Magnetic vortex consists of an in-plane circular domain called as chirality rotating clockwise (c = +1, CW) or counter-clockwise (c = -1, CCW) and an out-of-plane magnetic component denoted as polarity pointing either up (p = +1) or down (p = -1) [40,41]. Magnetic vortices have sparked enormous interests due to their compelling spin structures for understanding fundamental physics of nanospin behavior and also their potential in a wide range of applications such as logic device, data storage, transistor, signal transferring, and artificial skyrmion crystals [42][43][44][45][46]. In research of magnetic vortices, one of the most crucial topics is a fundamental understanding of nondeterministic behavior in the formation of vortex structure, which is directly related to the control of vortex structure, since it tremendously affects the performance of magnetic vortexbased nanospin devices.…”

Simultaneous control of magnetic topologies for reconfigurable vortex arrays

“…1,2 Because both circularity and polarity can be specified by two independent values, that is, c = ± 1 and p = ± 1, four distinct spin states can exist in a single magnetic element with the combination of circularity and polarity. Magnetic vortices have been intensively studied due to their compelling physical behavior [3][4][5][6][7] and their potential in a wide range of applications such as data storage, 8,9 signal transfer, [10][11][12] logic devices, 13 transistors 14 and artificial skyrmion crystals. [15][16][17][18] With respect to practical application of magnetic vortices in advanced nanotechnologies, one of the critical factors is the effective reconfigurability of two topologies, c and p, particularly within large and densely packed arrays of magnetic elements.…”