Imaging the magnetic nanowire cross-section and magnetic ordering within a suspended 3D artificial spin-ice: data

Artificial spin-ice systems are patterned arrays of magnetic nanoislands arranged into frustrated geometries and provide insight into the physics of ordering and emergence. The majority of these systems have been realized in two-dimensions, mainly due to the ease of fabrication, but with recent developments in advanced nanolithography, three-dimensional artificial spin ice (ASI) structures have become possible, providing a new paradigm in their study. In this work, a method is developed to fabricate 3DASI lattices over an aperture using two-photon lithography, thermal evaporation, and oxygen plasma exposure, allowing the probe of element-specific structural and magnetic information using soft x-ray microscopy with x-ray magnetic circular dichroism (XMCD) as magnetic contrast. Data description provided below:

Figure 2:

(a,b) Scanning electron microscopy image. Use standard image processing program such as ImageJ to open.

(c, d) Iron and Nickel thickness maps obtained through X-ray Absorption Spectroscopy (XAS) analysis. Processed using aXis2000 software. Accessible via standard image processing programs like ImageJ.

(e) Calculated thickness across nanowire width. Standard CSV file. Column A: Width (microns). Column E: Normalized Ni Thickness (nm). Column F: Normalized Fe Thickness (nm).

Figure 3:

(a,b,c) Scanning electron microscopy image. Use standard image processing program such as ImageJ to open.

(d) Atomic force microscopy image. Use standard SPM processing program such as Gwyddian to open.

(e) Calculated transmission of soft-x-rays through PMMA. Standard CSV file. Column A: Photon Energy (eV). Column B: Estimated transmission of PMMA 700 nm. Column C: Estimated transmission of PMMA 750 nm. Column D: Estimated transmission of PMMA 800 nm. Column E: Estimated transmission of PMMA 850 nm.

(f) Oxygen plasma exposure time vs Polymer nanowire thickness. Standard CSV file. Column A: Oxygen plasma exposure time (hours). Column B: Measured nanowire thickness (nm). Column C: Standard variation of nanowire thickness (nm).

Figure 4:

XAS transmission for Iron across L3 edge. Samples with varied oxygen plasma exposure times. Standard CSV File. Column A: Photon Energy – Sample 0 hours exposure (eV). Column B: Transmission intensity (arb. Units). Column C: Photon Energy – Sample 0.5 hours exposure (eV). Column D: Transmission intensity (arb. Units). Column E: Photon Energy – Sample 1 hour exposure (eV). Column F: Transmission intensity (arb. Units). Column G: Photon Energy – Sample 4 hours exposure (eV). Column H: Transmission intensity (arb. Units).

(a – inset) Ratio of Fe to Fe3O4. Standard CSV file. Column A: Oxygen plasma exposure time (hours). Column B: Fe Peak / Fe3O4 Peak.

TXM Optical density image. Use standard image processing program such as ImageJ to open.

Figure 5

(a, b) XMCD Images of pre and post application of a magnetic field. Use standard image processing program such as ImageJ to open.

(c, d) Normalised XMCD signal for SL1 and SL2 sublattices. Standard CSV files. Column A: Wire number. Column B: Pre- application of field measured XMCD intensity for SL1. Column C: Post-application of field measured XMCD intensity for SL1. Column D: Pre- application of field measured XMCD intensity for SL2. Column E: Post-application of field measured XMCD intensity for SL2.

(e) Intrawire XMCD comparison of wires. Standard CSV file. Column A: Wire number. Column B: Normalised XMCD signal for upwards wires for SL2. Column C: Normalised XMCD signal for downwards wires for SL2.

(f) Schematic only.

Figure 6

(a, b) Nickel L3 and L2 edge XMCD images. Use standard image processing program such as ImageJ to open.

Research results based upon these data are published at https://doi.org/10.1063/5.0176907