The Effect of Ion Implantation on Magnetic Properties of CoPd Multilayer Structures Possessing Perpendicular Anisotropy

Krichevsky, A.; Lavrenov, A.A.; Amos, Nissim; Hu, Bao-Gang; Taylor, Keith; Khizroev, Sakhrat

doi:10.1166/jno.2008.305

Cited by 3 publications

(3 citation statements)

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“…the domains vanish, indicating a lack of PMA, which is associated with a decrease in anisotropy energy Ku with ion implantation [30][31][32]. These results indicate that the B+ implantation is able to modify the magnetic properties of Co/Pd multilayer and that the implantation depth can be controlled by changing the Ta overcoat thickness [33][34][35][36].…”

Section: Methodsmentioning

confidence: 99%

Synaptic element for neuromorphic computing using a magnetic domain wall device with synthetic pinning sites

Jin¹,

Gan²,

Tan³

et al. 2019

J. Phys. D: Appl. Phys.

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The ability to make devices that mimic the human brain has been a subject of great interest in scientific research in recent years. Current artificial intelligence algorithms are primarily executed on the von Neumann hardware. This causes a bottleneck in processing speeds and is not energy efficient. In this work, we have demonstrated a synaptic element based on a magnetic domain wall device. The domain wall motion was controlled with the use of synthetic pinning sites, which were introduced by Boron (B+) ion-implantation for local modification of the magnetic properties. The magnetization switching process of a Co/Pd multilayer structure with perpendicular magnetic anisotropy was observed by using MagVision Kerr microscopy system. The B+ implantation depth was controlled by varying the thickness of a Ta overcoat layer. The Kerr microscopy results correlate with the electrical measurements of the wire which show multiple resistive states. The control of the domain wall motion with the synthetic pinning sites is demonstrated to be a reliable technique for neuromorphic applications.

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Section: Methodsmentioning

confidence: 99%

Synaptic element for neuromorphic computing using a magnetic domain wall device with synthetic pinning sites

Jin¹,

Gan²,

Tan³

et al. 2019

J. Phys. D: Appl. Phys.

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“…In general, the anisotropy decreases for the B + implanted samples. We propose that the decline is attributed to the change of Co/Pd interfaces caused by the implantation, as the PMA arises from Co and Pd interface …”

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confidence: 95%

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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“…The ion bombardments can reduce switching current density and enhance spin-charge conversion 14,[26][27][28][29] . However, the energies used in bombardment studies range in thousands of eV, and the heavy atom ions with such energies can severely affect the magnetic properties [30][31][32][33][34][35] .…”

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confidence: 99%

Enhancing damping-like efficiency by low-energy mixed ions bombardment

Bhatti,

Das,

Shaik

et al. 2024

Applied Physics Letters

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Pursuing enhanced spin–orbit torque (SOT) has become a significant focus for achieving energy-efficient spintronics devices. Researchers have explored different materials, layer engineering, and various post-deposition modification methods to realize higher SOT. Here, we have utilized the bombardment of mixed ions (Ar+ and He+ in various ratios) with 0.6 kV bias voltage to enhance the SOT efficiency in a Pt/Co/W stack. The bombardment modifies the physical properties (magnetic, electric, and structural) due to cascade collision, knocking off atoms (from the surface), and ion implantation. The increased percentage of He+ suppresses the drastic behavior of cascade collisions, and hence, the properties are tunable by changing the gas ratio. We exploited this behavior to design a material stack with enhanced SOT efficiency. We fabricated Hall bars to quantify SOT and observed a 4.5× increase in the effective damping-like efficiency. The efficiency and switching current density in the stack could be tuned by the variation of Ar:He ion ratio and the exposure duration. This study offers an easy route to tune the energy efficiency of spin devices, contributing to the advancement of next-generation spintronics.

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The Effect of Ion Implantation on Magnetic Properties of CoPd Multilayer Structures Possessing Perpendicular Anisotropy

Cited by 3 publications

References 0 publications

Synaptic element for neuromorphic computing using a magnetic domain wall device with synthetic pinning sites

Synaptic element for neuromorphic computing using a magnetic domain wall device with synthetic pinning sites

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

Enhancing damping-like efficiency by low-energy mixed ions bombardment

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