Switching behavior of single nanowires inside dense nickel nanowire arrays

Nielsch, Kornelius; Hertel, Riccardo; Wehrspohn, Ralf B.; Barthel, J.; Kirschner, J.; Gösele, U.; Fischer, Saskia F.; Kronmüller, H.

doi:10.1109/tmag.2002.801955

Cited by 77 publications

(58 citation statements)

References 22 publications

(24 reference statements)

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“…This conclusion is consistent with reports in similar systems in which the magnetostatic coupling effects were inferred indirectly from the analysis of the hysteresis loops. 10,13,14 Moreover, in our study, we observe a more consistent dependence of the strength of the magnetostatic coupling on the diameter of the nanowires than in earlier reported data, presumably due to the lack of inhomogeneous magnetization states for this particular magnetic field configuration and history. 4 However, as seen in the experimental data, while the amplitude of the peaks in the modified Henkel plots increases as the nanowire diameter is increased, this change does not scale linearly with the magnetic moment associated with the nanowires, i.e., proportional to the volume of the nanowires, as expected in a simple dipole approximation.…”

Section: Resultssupporting

confidence: 89%

“…While understanding how the size and geometry affect properties such as coercivity and thermal stability is critical for the applicability of these systems for magnetic storage, it is equally important to understand the magnetic interactions in high density arrays and the dependence of these couplings on the magnetic structure of the individual nano-objects. 9,10 In this paper, we investigate the magnetic interactions in ordered arrays of electrodeposited magnetic nanowires. For all the arrays investigated, the magnetostatic coupling between the nanowires plays an important role during the switching process as expected for a system of closely packed magnetic particles with large geometric anisotropy.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of magnetic interactions in large arrays of magnetic nanowires

Fodor

Tsoi

Wenger

2008

Journal of Applied Physics

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The magnetic interactions in large arrays of ordered magnetic nanowires with 12-48 nm diameter and 55-95 nm spacing were investigated using modified Henkel plots. The measurements for nanowire arrays ac demagnetized with the field applied parallel to the nanowire axis ͑the easy magnetization axis͒ indicate that the dominant interaction during the switching process is the magnetostatic coupling between the nanowires. Nevertheless, while the strength of the magnetostatic interactions increases with the magnetic moment associated with the nanowires, the increase is not linear with respect to the volume of the nanowires. Moreover, the dependence of the remanence curves on the field history suggests that even for magnetic nanowire systems with high geometric anisotropy, the magnetic pole structure of the nanowires can be complex. This conclusion is also supported by the field dependence of the initial magnetization curves.

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Section: Resultssupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Investigation of magnetic interactions in large arrays of magnetic nanowires

Fodor

Tsoi

Wenger

2008

Journal of Applied Physics

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“…Increasing the magnetic field strength by -2 mT will lead to the propagation of the domain wall, i.e. a rapid switching process, as expected [49,50].…”

Section: Properties Of Individual Nanomagnetsmentioning

confidence: 56%

Intra-wire coupling in segmented Ni/Cu nanowires deposited by electrodeposition

Sergelius¹,

Lee²,

Fruchart³

et al. 2017

Nanotechnology

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Segmented magnetic nanowires are a promising route for the development of three dimensional data storage techniques. Such devices require a control of the coercive field and the coupling mechanisms between individual magnetic elements. In our study, we investigate electrodeposited nanomagnets within host templates using vibrating sample magnetometry and observe a strong dependence between nanowire length and coercive field (25 nm to 5 µm) and diameter (25 nm to 45 nm). A transition from a magnetization reversal through coherent rotation to domain wall propagation is observed at an aspect ratio of approximately 2. Our results are further reinforced via micromagnetic simulations and angle dependent hysteresis loops. The found behavior is exploited to create nanowires consisting of a fixed and a free segment in a spin-valve like structure. The wires are released from the membrane and electrically contacted, displaying a giant magnetoresistance effect that is attributed to individual switching of the coupled nanomagnets. We develop a simple analytical model to describe the observed switching phenomena and to predict stable and unstable regimes in coupled nanomagnets of certain geometries.-2 - INTRODUCTIONIn the investigation of nanomagnet assemblies, the focus has mainly been on lithographicallypatterned, planar structures, which can be used as logic devices capable of executing Boolean logic operations [1][2][3][4][5][6][7][8]. Often applications are sought within high density recording, bit patterned media [9][10][11][12] or MRAM devices [1,13], however since the bit size of modern hard disk drives (approx. 20x20 nm²) is already lower than what is achievable with most lithography techniques [14], potential use is limited. Therefore, the use of the third dimension is an appealing approach. Studies on alternating, vertical stacks of magnetic and non-magnetic materials have already been published, in which a three dimensional shift register is investigated, that is capable of storing and shifting several bits of information as solitons within a single column [15][16][17][18][19]. These shift registers are coupled via RKKY interaction and its oscillatory nature allows for an additional degree of freedom in the design of the device, but as a drawback the samples are very demanding with regard to sample quality and purity. A soliton, which is the bearer of information, is a magnetic frustration within a 1D chain of magnetic moments. It is thinkable to induce such a soliton using dipolar coupling instead of RKKY, simply by magnetizing two nanomagnets in the same direction and placing them next to each other (transversal soliton [20]). Another possibility would be to magnetize them in opposing direction and place them in a head-to-head or tail-to-tail configuration (longitudinal soliton, Figure 1). The coupling strength is then defined by the material properties and the distance of both nanomagnets. Such kinds of nanowires can be synthesized within porous anodic aluminum oxide (AAO) templates [21-23] using electro...

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“…2͑b͒ and 2͑c͒ cannot be explained through coherent magnetization rotation. Indeed, computer simulations by Ross et al 15 and Nielsch et al 16 show that the magnetization process in the nanostructures is evidently different from the abrupt coherent magnetization reversal predicted by SW model. For the nanostructures with small aspect ratio, the magnetization occurs through incoherent magnetization reversal, 15 whereas in nanowires domain walls nucleate at the ends of the wires and propagate along the wires.…”

Section: Resultsmentioning

confidence: 95%

Fabrication and magnetic properties of Fe nanostructures in anodic alumina membrane

Lim

Chae

Lee

et al. 2010

Journal of Applied Physics

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Several Fe nanostructures with different lengths, diameters, and separations of the constituting magnetic components have been synthesized using anodized alumina membranes ͑AAMs͒ to understand the influence of these parameters on their magnetic properties. Fe nanostructures with high crystallinity and ͑110͒ orientation were synthesized by electrodeposition at room temperature in regular AAMs and mild-hard AAM ͑Mi-Ha AAM͒. Fe nanostructures with different aspect ratios ͑1:1, 1:10, and 1:75͒ in the form of nanodots, nanorods, or nanowires were synthesized in regular AAMs with the 100 nm interpore distance. Mi-Ha AAMs with two different pore sizes ͑70 and 120 nm͒ and 250 nm interpore distances were used to investigate the effect of the interactions and of the diameter of the wires on their magnetic behavior. Nearly linear magnetization characteristics with small coercivity, observed for Fe nanowires, suggest the magnetization rotation to be the predominant magnetization process for the field applied transverse to the wires. The anisotropy of the arrays was governed by the shape anisotropy of the magnetic objects with different aspect ratios. Reduced interactions between the nanowires grown in Mi-Ha AAMs resulted in enhancement of the average anisotropy. It is believed that due to difference in spin configuration, the increased diameter of the nanowires led to reduction in the coercivity in the case of the field applied along the wires.

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Switching behavior of single nanowires inside dense nickel nanowire arrays

Cited by 77 publications

References 22 publications

Investigation of magnetic interactions in large arrays of magnetic nanowires

Investigation of magnetic interactions in large arrays of magnetic nanowires

Intra-wire coupling in segmented Ni/Cu nanowires deposited by electrodeposition

Fabrication and magnetic properties of Fe nanostructures in anodic alumina membrane

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