37 lines
1.6 KiB
Markdown
37 lines
1.6 KiB
Markdown
# MFM Domain Generation
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Generate the stray field from a periodic pattern of parallel magnetic stripe domains with alternating up/down magnetization. Equivalent to Gwyddion's mfm_parallel.c.
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## Inputs
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| Name | Type | Required | Description |
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|------|------|----------|-------------|
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| field | DATA_FIELD | Yes | Topography used for grid dimensions |
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## Outputs
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| Name | Type | Description |
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|------|------|-------------|
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| hz | DATA_FIELD | z-component of the stray field (A/m) |
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| dhz_dz | DATA_FIELD | Vertical gradient of the stray field (A/m²) |
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## Controls
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| Name | Type | Default | Description |
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|------|------|---------|-------------|
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| height | FLOAT | 50e-9 | Tip-sample separation in metres |
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| thickness | FLOAT | 20e-9 | Magnetic film thickness in metres |
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| magnetization | FLOAT | 1e6 | Saturation magnetization in A/m |
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| stripe_width_a | FLOAT | 200e-9 | Width of the A (+M) domain in metres |
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| stripe_width_b | FLOAT | 200e-9 | Width of the B (-M) domain in metres |
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| gap | FLOAT | 0.0 | Domain wall gap between stripes in metres |
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## Notes
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- Domains alternate between A (+M, magnetization up) and B (-M, magnetization down) with an optional gap of zero magnetization between them.
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- The stray field is computed via FFT of the magnetization profile using an exponential decay transfer function.
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- The field is uniform along y; stripes run parallel to the y-axis.
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- dHz/dz is proportional to the MFM phase signal (force gradient), making it the quantity most directly comparable to raw MFM images.
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- Useful for simulating MFM calibration samples and testing MFM analysis workflows.
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- Typical stripe widths range from 100 nm to several microns.
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