Depinning process of magnetic domain walls in cylindrical nanowires with a chemical constraint

Castilla, David; Maícas, M.; Prieto, José Luis Rodríguez-Villasante y; Proença, Mariana P.

doi:10.1088/1361-6463/aa59b6

Cited by 8 publications

(5 citation statements)

References 41 publications

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“…Despite the time needed or the velocity used, the DW formed inside each segment during the domain movement can be described in the three cases as a transversal like DW. This result is in good agreement with Castilla et al [20], where it is reported that the pinning of a DW in a chemical constraint (the Au segment in this case) transforms any kind of DW into a transversal DW, which is also observed in these simulations. The movement of the transversal DW under the application of a spin current has been studied by the animation of the storage process in the geometrical case, which is shown in Supplementary information Video S1.…”

Section: Bit Movementsupporting

confidence: 93%

“…Chemical constraints consist of sections within the nanowire where the chemical composition changes with respect to the rest of the sample. If one segment of non-magnetic material is grown in the middle of two magnetic segments, the DW can be pinned at this constraint [20,21]. Its use avoids the presence of physical constraints, so the geometry does not change along the wire and the undesired overheating is eliminated.…”

Section: Introductionmentioning

confidence: 99%

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A Novel Design of a 3D Racetrack Memory Based on Functional Segments in Cylindrical Nanowire Arrays

Rial

Proença

2020

Nanomaterials

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A racetrack memory is a device where the information is stored as magnetic domains (bits) along a nanowire (track). To read and record the information, the bits are moved along the track by current pulses until they reach the reading/writing heads. In particular, 3D racetrack memory devices use arrays of vertically aligned wires (tracks), thus enhancing storage density. In this work, we propose a novel 3D racetrack memory configuration based on functional segments inside cylindrical nanowire arrays. The innovative idea is the integration of the writing element inside the racetrack itself, avoiding the need to implement external writing heads next to the track. The use of selective magnetic segments inside one nanowire allows the creation of writing and storage sections inside the same track, separated by chemical constraints identical to those separating the bits. Using micromagnetic simulations, our study reveals that if the writing section is composed of two segments with different coercivities, one can reverse its magnetization independently from the rest of the memory device by applying an external magnetic field. Spin-polarized current pulses then move the information bits along selected tracks, completing the writing process by pushing the new bit into the storage section of the wire. Finally, we have proven the efficacy of this system inside an array of 7 nanowires, opening the possibility to use this configuration in a 3D racetrack memory device composed of an array of thousands of nanowires produced by low-cost and high-yield template-electrodeposition methods.

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Section: Bit Movementsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

A Novel Design of a 3D Racetrack Memory Based on Functional Segments in Cylindrical Nanowire Arrays

Rial

Proença

2020

Nanomaterials

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“…The thermal contribution is even more relevant when a physical constriction (notch) is used to trap the DW. A possible alternative would be to work in a weak pinning regime (very shallow notches) or using chemical defects to pin the DW 28 , so there is not an enhanced Joule heating associated to the pinning point. Some of the conclusions drawn in this work though have to be taken cautiously in experiments of DW depinning using materials with perpendicular magnetic anisotropy (PMA) 29 , where the domain wall movement is thermally activated.…”

Section: Discussionmentioning

confidence: 99%

Influence of the thermal contact resistance in current-induced domain wall depinning

López¹,

Ramos²,

Muñoz³

et al. 2017

J. Phys. D: Appl. Phys.

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In this work we study the influence of the thermal contact resistance on the temperature of a typical nanostripe used in current induced magnetic domain wall movement or depinning. The thermal contact resistance arises from an imperfect heat transport across the interface between the metallic ferromagnetic nanostripe and the substrate. We show that this parameter, which is likely nonzero in any experimental device, increases the temperature in the nanostripe considerably. When the current is injected in the nanostripe in nanosecond long pulses, the larger temperature also implies a reduction of the effective current density delivered by the pulse generator. Both, the thermal contact resistance and the dynamic response of the pulse generator, are usually neglected in theoretical estimations of the influence of spin transfer torque on domain wall displacement and depinning. Here we show that only if the thermal contact resistance and the electric resistivity of the ferromagnetic nanostripe are optimized to the best values reported in the bibliography, the Joule heating may not be so crucial for current densities of the order of 10 8 A/cm 2 . Also, the use of physical constrictions (notch) to pin the magnetic domain wall may complicate the interpretation of the results as they always come together with relevant thermal gradients.

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“…Thermally stable recorded data require keeping DWs at a precise position within the nanowire for a certain period, which could be a period of a few years if the data are archived. Artificial nanowires (NW) with naturally formed defects of different geometries acting as trapping sites have also been investigated using both numerical simulation and experimental observations [4,[31][32][33]. Several studies have also reported that experimentally creating notches using lithography helps to block or pin DWs [5,6,[34][35][36][37][38][39][40][41].…”

Section: Introductionmentioning

confidence: 99%

Staggered Magnetic Nanowire Devices for Effective Domain-Wall Pinning in Racetrack Memory

et al. 2019

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Depinning process of magnetic domain walls in cylindrical nanowires with a chemical constraint

Cited by 8 publications

References 41 publications

A Novel Design of a 3D Racetrack Memory Based on Functional Segments in Cylindrical Nanowire Arrays

A Novel Design of a 3D Racetrack Memory Based on Functional Segments in Cylindrical Nanowire Arrays

Influence of the thermal contact resistance in current-induced domain wall depinning

Staggered Magnetic Nanowire Devices for Effective Domain-Wall Pinning in Racetrack Memory

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