Depinning of vortex domain walls from an asymmetric notch in a permalloy nanowire

Zhu, Weiwei; Liao, Jung-Wei; Zhang, Zongzhi; Ma, Bin; Liu, Yaowen; Huang, Zhaocong; Hu, Xuefeng; Ding, Anwei; Wu, Jing; Xu, Yongbing

doi:10.1063/1.4745788

Cited by 23 publications

(23 citation statements)

References 24 publications

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“…The M - H loops for the other nanowires can be seen in Supplementary Material A. It needs to be emphasized that the M - H loop corresponds to the variation of the total magnetic moment of the nanowire versus the applied magnetic field ( H a ), which is different from that obtained from a small local area at the nanowire in refs 11,22. The formation of the M - H loops shown in Fig.…”

Section: Resultsmentioning

confidence: 94%

“…Very recently, W. Zhu et al 11. have observed two distinct depining fields by a high sensitive focused magneto-optical Kerr effect (FMOKE) magnetometer in a permalloy nanowire with an asymmetric notch.…”

mentioning

confidence: 99%

“…Those studies reported positive 6 7 8 and negative 9 10 DWMR effects due to spin-dependent scattering and anisotropic magnetoresistance (AMR), respectively. Generally speaking, the pinning and depinning processes of DWs can be modulated by external magnetic field directly 2 11 or by spin-polarized current due to spin-transfer torque (STT) effect 1 8 10 12 13 . In order to better understand and control the pinning/depinning of DWs, various magnetic nanowire systems have been studied 2 4 10 14 15 .…”

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confidence: 99%

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Depinning of domain walls in permalloy nanowires with asymmetric notches

Gao

You

Ruan

et al. 2016

Sci Rep

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Effective control of the domain wall (DW) motion along the magnetic nanowires is of great importance for fundamental research and potential application in spintronic devices. In this work, a series of permalloy nanowires with an asymmetric notch in the middle were fabricated with only varying the width (d) of the right arm from 200 nm to 1000 nm. The detailed pinning and depinning processes of DWs in these nanowires have been studied by using focused magneto-optic Kerr effect (FMOKE) magnetometer, magnetic force microscopy (MFM) and micromagnetic simulation. The experimental results unambiguously exhibit the presence of a DW pinned at the notch in a typical sample with d equal to 500 nm. At a certain range of 200 nm < d < 500 nm, both the experimental and simulated results show that the DW can maintain or change its chirality randomly during passing through the notch, resulting in two DW depinning fields. Those two depinning fields have opposite d dependences, which may be originated from different potential well/barrier generated by the asymmetric notch with varying d.

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Section: Resultsmentioning

confidence: 94%

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confidence: 99%

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confidence: 99%

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Depinning of domain walls in permalloy nanowires with asymmetric notches

Gao

You

Ruan

et al. 2016

Sci Rep

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“…At a diameter of 350 nm, a three-dimensional helical DW is expected to form, 11,12 while at diameters between 40 and 50 nm, a Bloch-point DW or a transverse DW is observed. [13][14][15] Although the DW dynamics in planar nanowires are relatively well understood, [16][17][18] there is very limited research work reported on the dynamics of the threedimensional helical DWs.…”

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confidence: 99%

Dynamics of three-dimensional helical domain wall in cylindrical NiFe nanowires

Wong

Sekhar

Gan

et al. 2015

Journal of Applied Physics

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We report on a micromagnetic study on the dynamics of current-driven helical domain wall (DW) in cylindrical NiFe nanowires. The helical DW is a three-dimensional transition region between magnetizations with clockwise and anticlockwise vortex orientations. A minimum current density is needed to overcome an intrinsic pinning to drive the helical DW, and the propagation along the nanowire is accompanied by a rotational motion. As the driving current strength is increased, the rotation ceases while the DW propagates at an increased velocity. However, a velocity barrier is experienced which results in the decrease of the DW mobility. Throughout its motion, the propagated helical DW maintains a stable profile without showing any sign of structural breakdown even at relatively high driving current.

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“…This kind of data storage presumes to perform approximately 100 times faster than commercial technology such as flash or harddisk drive (HDD) memory [7]. Many studies reported about the depinning process driven by magnetic field [8][9][10][11] and spin polarized current [5,[12][13][14][15] in the notched nanowires. It was known that the depinning process was directly influenced by the shape of the constriction as the pinning site and the DW inner structure.…”

Section: Introductionmentioning

confidence: 99%

Current driven domain wall depinning in notched Permalloy nanowires

Kurniawan

Djuhana

2016

AIP Conference Proceedings

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In this work, we have investigated the domain wall (DW) depinning behavior in the notched nanowire by a micromagnetic simulation. A transverse domain wall (TW) was initially positioned at the center of notch and 1 ns length current pulse was applied to depin the DW with respect to the notch size s and the wire width variation. We have observed the depinning current density J d which was a minimum current to escape DW from the notch. It was found that the depinning current density decreased as the wire width and the notch size increased. In the depinning process, we observed the inner structure of DW generally transformed from TW to anti-vortex wall (AVW). Interestingly, for the case of s less than 70 nm, AVW formed and depinned closely to the period when current pulse was active, while for s larger than 70 nm, AVW formed until the current pulse went to zero and then depinned after flipped TW was formed. It can be explained that the transformation of DW inner structures were affected by the spin torque energy and contributed to DW depinning behavior from the notched nanowires.

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Depinning of vortex domain walls from an asymmetric notch in a permalloy nanowire

Cited by 23 publications

References 24 publications

Depinning of domain walls in permalloy nanowires with asymmetric notches

Depinning of domain walls in permalloy nanowires with asymmetric notches

Dynamics of three-dimensional helical domain wall in cylindrical NiFe nanowires

Current driven domain wall depinning in notched Permalloy nanowires

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