Highly Efficient In-Line Magnetic Domain Wall Injector

Phung, Timothy; Pushp, Aakash; Thomas, Luc; Rettner, Charles; Yang, See‐Hun; Ryu, Kwang-Su; Baglin, J. E. E.; Hughes, Brian; Parkin, Stuart S. P.

doi:10.1021/nl503391k

Cited by 35 publications

(31 citation statements)

References 33 publications

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“…30,38,42,43 In this work, we demonstrate a novel mechanism to control the injection of chiral DWs in perpendicularly magnetized Pt/Co/AlO x wires, which exploits the DMI at the boundary between adjacent in-plane (IP) and out-of-plane (OOP) magnetic regions. Unlike previous investigations based on boundaries with orthogonal magnetization alignment, which have been employed for DW injection using SOTs 44 and spin-transfer torques 19 , our method combines the SOTs with the chiral coupling between IP and OOP regions induced by the DMI. 45 This coupling is found to strongly affect the DW nucleation process.…”

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confidence: 99%

Chiral Domain Wall Injector Driven by Spin–Orbit Torques

et al. 2019

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Memory and logic devices that encode information in magnetic domains rely on the controlled injection of domain walls to reach their full potential. In this work, we exploit the chiral coupling induced by the Dzyaloshinskii-Moriya interaction between in-plane and out-of-plane magnetized regions of a Pt/Co/AlO x trilayer in combination with current-driven spin-orbit torques to control the injection of domain walls into magnetic conduits. We demonstrate that the current-induced domain nucleation is strongly inhibited for magnetic configurations stabilized by the chiral coupling and promoted for those that have the opposite chirality. These configurations allow for 1 arXiv:2003.11805v1 [cond-mat.mes-hall] 26 Mar 2020 efficient domain wall injection using current densities of the order of 4×10 11 Am −2 , which are lower than those used in other injection schemes. Furthermore, by setting the orientation of the in-plane magnetization using an external field, we demonstrate the use of a chiral domain wall injector to create a controlled sequence of alternating domains in a racetrack structure driven by a steady stream of unipolar current pulses. Main TextThe nucleation of magnetic domains underpins magnetization reversal processes and, consequently, the functioning of most types of magnetic storage devices. Domain wall (DW) racetrack memory and logic devices, in particular, require reliable control over domain nucleation and current-induced DW propagation in order to work efficiently. 1-3 The problem of domain nucleation was first addressed by modifying the magnetic anisotropy of the nucleation sites using altered shapes 4-6 or ion irradiation of magnetic structures, 7-12 which favor magnetization reversal at specific locations. These methods are commonly used in field-induced domain nucleation and DW propagation studies. [13][14][15][16] Current-induced domain nucleation techniques based on the Oersted field produced by a narrow write line, 17 spin-transfer torque switching using magnetic tunnel junctions 18 and using magnetization boundaries where the magnetization of the two adjacent regions are orthogonally aligned 19 have been shown to mitigate the shortcomings of field nucleation. These methods offer faster and more localized domain nucleation at the cost of higher device complexity.A significant leap forward in magnetic writing was made with the advent of spin-orbit torques (SOTs), 20-24 which emerge at ferromagnet/heavy metal interfaces. 25 Ever since the

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confidence: 99%

Chiral Domain Wall Injector Driven by Spin–Orbit Torques

et al. 2019

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“…We designed a special stripe magnetic wire as schematically illustrated in Figure 1. One end of the stripe magnetic wire is connected to a diamond-shaped pad which acts as a DW injector [4], and the other end is sharply pointed to prevent the nucleation of a DW from this end [5]. Then the different depth trenches were fabricated at the middle of the stripe.…”

Section: Methodsmentioning

confidence: 99%

Control Domain Wall Motion by Different Depth Trenches in Submicron Permalloy Wires

Wu¹,

Yen²

2019

Preprint

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Domain walls were studied for permalloy wires with different depth trenches (500 nm wide, 30 nm thick, 7.5 µm long, the depth of the trench was 0, 4, 5, 8, 10, 12 and 15nm). Permalloy (Ni80Fe20) wires were fabricated by electron beam lithography and Ar ion milling. When the depth of trench is smaller than 12 nm, the switching field (Hs) is increasing with the deeper trench. However, the depth of trench is bigger than half depth of thickness, the Hs is decreasing with the deeper trench. We believed that Hs increased as the trench depth increased was because the magnetic diploes force increased between the magnetic poles on two sides of the trench. The domains of the wires were divided by the trenches and the domain walls were pinned on the trenches these were confirmed by magnetic force microscopy images.

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“…Fabricated elliptical pads are used to obtain vortex domain walls and investigate the domain wall injection process. According to these studies, variations in pad geometry create distinct domain wall injection modes (angle, position, and wall type), thus affecting the magnetic reversal process [13,14]. The magnetization of the sample could be magnetic-or current-driven so as to change its magnetic state.…”

Section: Introductionmentioning

confidence: 99%

Domain Wall Injection in Spin Valve Systems with Reservoirs of Different Geometries

Yen

2020

Crystals

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This study investigates nanostrips in Co/Cu/Py spin valve structures by connecting one side to domain wall reservoirs of different shapes in order to manipulate the switching field. The switching field increases according to the injection geometry; a diamond-shape reservior generates the largest switching field, followed by square-shape and then tip shape reservoirs. Simulation indicated the same results, showing that the vortex domain walls nucleated at the junction, but the pinning force increased as the magnetic transition area became larger (the injection angle became smaller). Therefore, by controlling the domain wall injection angles, the switching fields of the nanostrips can be manipulated.

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Highly Efficient In-Line Magnetic Domain Wall Injector

Cited by 35 publications

References 33 publications

Chiral Domain Wall Injector Driven by Spin–Orbit Torques

Chiral Domain Wall Injector Driven by Spin–Orbit Torques

Control Domain Wall Motion by Different Depth Trenches in Submicron Permalloy Wires

Domain Wall Injection in Spin Valve Systems with Reservoirs of Different Geometries

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