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Single crystalline cylindrical nanowires - toward dense 3D arrays of magnetic vortices.

Ivanov YP, Chuvilin A, Vivas LG, Kosel J, Chubykalo-Fesenko O, Vázquez M - Sci Rep (2016)

Bottom Line: Magnetic vortex-based media have recently been proposed for several applications of nanotechnology; however, because lithography is typically used for their preparation, their low-cost, large-scale fabrication is a challenge.In this work, we present this type of nanoscale magnetic structures that can hold multiple stable magnetic vortex domains at remanence with different chiralities.The data we present here introduce a route toward the concept of 3-dimensional vortex-based magnetic memories.

View Article: PubMed Central - PubMed

Affiliation: King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia.

ABSTRACT
Magnetic vortex-based media have recently been proposed for several applications of nanotechnology; however, because lithography is typically used for their preparation, their low-cost, large-scale fabrication is a challenge. One solution may be to use arrays of densely packed cobalt nanowires that have been efficiently fabricated by electrodeposition. In this work, we present this type of nanoscale magnetic structures that can hold multiple stable magnetic vortex domains at remanence with different chiralities. The stable vortex state is observed in arrays of monocrystalline cobalt nanowires with diameters as small as 45 nm and lengths longer than 200 nm with vanishing magnetic cross talk between closely packed neighboring wires in the array. Lorentz microscopy, electron holography and magnetic force microscopy, supported by micromagnetic simulations, show that the structure of the vortex state can be adjusted by varying the aspect ratio of the nanowires. The data we present here introduce a route toward the concept of 3-dimensional vortex-based magnetic memories.

No MeSH data available.


Related in: MedlinePlus

(a) BF-TEM and (b) mixed LorTEM images at over- (+200 μm, red spots) and under-focused (−200 μm, green sports) conditions of an array of NWs with a 75-nm diameter at remanence (red and green spots correspond to NWs with opposite magnetization chirality). (c) The original interferogram, (d) the reconstructed image of an array of NWs with a 75-nm diameter at remanence (high- and low-phase values are represented by two color sequences corresponding to the clockwise and anticlockwise rotation of NW magnetization) and (e) shows the contour lines that correspond to the B⊥.
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f4: (a) BF-TEM and (b) mixed LorTEM images at over- (+200 μm, red spots) and under-focused (−200 μm, green sports) conditions of an array of NWs with a 75-nm diameter at remanence (red and green spots correspond to NWs with opposite magnetization chirality). (c) The original interferogram, (d) the reconstructed image of an array of NWs with a 75-nm diameter at remanence (high- and low-phase values are represented by two color sequences corresponding to the clockwise and anticlockwise rotation of NW magnetization) and (e) shows the contour lines that correspond to the B⊥.

Mentions: To stabilize the vortex state, we increased the diameter of NWs to 75 nm, as shown in Fig. 4. Figure 4b shows the mixed over- and under-focused images of the NW array presented in Fig. 4a (red and green spots correspond to NWs with opposite magnetization chirality). Only a few NWs exhibited a ground state different from the vortex state, and as shown in the reconstructed hologram image in Fig. 4e, which is a magnetization in plane with NW diameter. Consequently, the number of NWs with a vortex state was much larger than that of those with an in-plane state.


Single crystalline cylindrical nanowires - toward dense 3D arrays of magnetic vortices.

Ivanov YP, Chuvilin A, Vivas LG, Kosel J, Chubykalo-Fesenko O, Vázquez M - Sci Rep (2016)

(a) BF-TEM and (b) mixed LorTEM images at over- (+200 μm, red spots) and under-focused (−200 μm, green sports) conditions of an array of NWs with a 75-nm diameter at remanence (red and green spots correspond to NWs with opposite magnetization chirality). (c) The original interferogram, (d) the reconstructed image of an array of NWs with a 75-nm diameter at remanence (high- and low-phase values are represented by two color sequences corresponding to the clockwise and anticlockwise rotation of NW magnetization) and (e) shows the contour lines that correspond to the B⊥.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4814901&req=5

f4: (a) BF-TEM and (b) mixed LorTEM images at over- (+200 μm, red spots) and under-focused (−200 μm, green sports) conditions of an array of NWs with a 75-nm diameter at remanence (red and green spots correspond to NWs with opposite magnetization chirality). (c) The original interferogram, (d) the reconstructed image of an array of NWs with a 75-nm diameter at remanence (high- and low-phase values are represented by two color sequences corresponding to the clockwise and anticlockwise rotation of NW magnetization) and (e) shows the contour lines that correspond to the B⊥.
Mentions: To stabilize the vortex state, we increased the diameter of NWs to 75 nm, as shown in Fig. 4. Figure 4b shows the mixed over- and under-focused images of the NW array presented in Fig. 4a (red and green spots correspond to NWs with opposite magnetization chirality). Only a few NWs exhibited a ground state different from the vortex state, and as shown in the reconstructed hologram image in Fig. 4e, which is a magnetization in plane with NW diameter. Consequently, the number of NWs with a vortex state was much larger than that of those with an in-plane state.

Bottom Line: Magnetic vortex-based media have recently been proposed for several applications of nanotechnology; however, because lithography is typically used for their preparation, their low-cost, large-scale fabrication is a challenge.In this work, we present this type of nanoscale magnetic structures that can hold multiple stable magnetic vortex domains at remanence with different chiralities.The data we present here introduce a route toward the concept of 3-dimensional vortex-based magnetic memories.

View Article: PubMed Central - PubMed

Affiliation: King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia.

ABSTRACT
Magnetic vortex-based media have recently been proposed for several applications of nanotechnology; however, because lithography is typically used for their preparation, their low-cost, large-scale fabrication is a challenge. One solution may be to use arrays of densely packed cobalt nanowires that have been efficiently fabricated by electrodeposition. In this work, we present this type of nanoscale magnetic structures that can hold multiple stable magnetic vortex domains at remanence with different chiralities. The stable vortex state is observed in arrays of monocrystalline cobalt nanowires with diameters as small as 45 nm and lengths longer than 200 nm with vanishing magnetic cross talk between closely packed neighboring wires in the array. Lorentz microscopy, electron holography and magnetic force microscopy, supported by micromagnetic simulations, show that the structure of the vortex state can be adjusted by varying the aspect ratio of the nanowires. The data we present here introduce a route toward the concept of 3-dimensional vortex-based magnetic memories.

No MeSH data available.


Related in: MedlinePlus