Domain wall dynamics in Co/Pd multilayers

Gadetsky, S.

doi:10.1109/20.490382

Cited by 4 publications

(2 citation statements)

References 13 publications

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“…[5][6][7] The reversal behavior of magnetic thin films with perpendicular anisotropy has been studied extensively 8 and it is widely accepted that the reversal mechanism is one dominated by nucleation followed by rapid domain-wall motion. 9 Reversal is nucleated at regions of low anisotropy which for materials of similar distributions of anisotropy means that the nucleation field is related to the average anisotropy in a consistent manner. The reversal behavior of Co/Pd multilayers can be discussed in the context of the Mansuripur's two-coercivity model, where two extreme cases can be identified.…”

Section: Introductionmentioning

confidence: 99%

Magnetisation reversal in anisotropy graded Co/Pd multilayers

Barton

Thomson

2015

Journal of Applied Physics

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We demonstrate high precision controllability of the magnetization reversal nucleation process in [Co/Pd]8 multilayer films consisting of two sets of bilayers with high and low perpendicular anisotropy, respectively. The anisotropy of the entire film is set by the degree of Co/Pd interfacial mixing during deposition which provides fine control of the anisotropy of an individual bilayer in the multilayer stack. The relative number of each type of bilayer is used to select the magnetisation reversal behavior such that changing one bilayer changes the properties of the entire multilayer through anisotropy averaging. A simple extension to the sputtering protocol would provide multilayer films with fully graded anisotropy, while maintaining a constant saturation magnetization opening new possibilities for the creation of highly engineered multilayer structures for spin torque devices and future magnetic recording media.

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Section: Introductionmentioning

confidence: 99%

Magnetisation reversal in anisotropy graded Co/Pd multilayers

Barton

Thomson

2015

Journal of Applied Physics

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“…When a current was sent with a density of 5 × 10 10 A m −2 , the domain walls propagated to the end of nanowire without stopping. The domain wall velocity was found to be 8 m s −1 . Figure (b1–b3) illustrate the scenario for the nanowires with modified regions.…”

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confidence: 97%

Nanoscale Compositional Modification in Co/Pd Multilayers for Controllable Domain Wall Pinning in Racetrack Memory

Jin

Kumar

Gan

et al. 2018

Physica Rapid Research Ltrs

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In the era of social media, storage of information plays an important role. Magnetic domain wall memory devices are promising alternatives to hard disk drives for high-capacity storage. One of the challenges in making these devices for practical application is a precise control of domain wall displacement in nanowires. Researchers have extensively studied domain wall pinning based on topographical notches fabricated by lithography. However, scaling the domain wall memory to nanoscale requires better domain wall pinning strategies. In this letter, we demonstrate that the localized modification of magnetic properties in Co/Pd multilayer-based nanowires by ion implantation is an effective non-topographical approach to pin domain walls. First, by micromagnetic simulations, it is shown that the areas, where the composition is modified to tune the anisotropy and magnetization, act as domain wall pinning centers. Experimentally, from magnetization measurements and X-ray diffraction measurements at the thin film level, it is shown that the ion-implantation is effective in changing magnetic anisotropy. Devices have also been fabricated and, using Kerr images at different applied fields, it is shown that the domain walls are pinned at the B þ ion-implanted regions. These results demonstrate that localized compositional modification using ion-implantation can pin domain walls precisely. The achieved results are useful toward realizing high-capacity information storage.Domain wall (DW)-based devices such as racetrack memory have been proposed as promising candidates for high capacity, non-volatile information storage to replace hard disk drives. [1,2] In DW memory (DWM) with a perpendicular magnetic anisotropy (PMA), the domains with magnetization pointing up represent "1" and the regions with magnetization pointing down represent "0." [2,3] In order to read and write information, the DWs are moved by an electrical current which causes motion by the spin-transfer torque (STT) mechanism. [4][5][6][7] Spin Hall effect in heavy metal/ferromagnetic/insulator structures is another mechanism in which a torque is exerted by pure spin current. [8,9] In comparison to STT driving DW motion, pure spin-polarized current gives a high speed performance of DW devices. [10,11] The speed of DW motion in certain designs could reach km s À1 . [11] In order to increase the capacity of DWM, researchers proposed fabricating U-shape vertical nanowire to store data, like the trees planted in the forest. However, fabrication of such devices is challenging particularly for commercial purposes. The other structure is horizontal stripe shape, which suffers from the data storing overflowing issues because the two ends of nanowire cannot be connected. Zhang et al. [12] proposed a ring structure with DW ratchets, which could be utilized for addressing the data overflow issue without any additional overhead.For DW-based devices, the propagation of DWs show a stochastic behavior. This stochastic manner was a significant challenge for magnetic recording comm...

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Dynamics of Magnetization Reversal: From Continuous to Patterned Ferromagnetic Films

Ferré

Topics in Applied Physics

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Domain wall dynamics in Co/Pd multilayers

Cited by 4 publications

References 13 publications

Magnetisation reversal in anisotropy graded Co/Pd multilayers

Magnetisation reversal in anisotropy graded Co/Pd multilayers

Nanoscale Compositional Modification in Co/Pd Multilayers for Controllable Domain Wall Pinning in Racetrack Memory

Dynamics of Magnetization Reversal: From Continuous to Patterned Ferromagnetic Films

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