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docs/nodes/MFM Analysis.md

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+# MFM Analysis
+
+Magnetic Force Microscopy analysis: convert between MFM phase/force gradient and magnetic field quantities using Fourier-domain transfer functions. Equivalent to Gwyddion's mfm_*.c modules.
+
+## Inputs
+
+| Name | Type | Required | Description |
+|------|------|----------|-------------|
+| field | DATA_FIELD | Yes | Input MFM data (phase, force gradient, or field) |
+
+## Outputs
+
+| Name | Type | Description |
+|------|------|-------------|
+| result | DATA_FIELD | Converted MFM quantity |
+
+## Controls
+
+| Name | Type | Default | Description |
+|------|------|---------|-------------|
+| operation | dropdown | phase_to_force_gradient | Conversion: phase_to_force_gradient, force_gradient_to_field, charge_density, magnetisation |
+| lift_height | FLOAT | 50e-9 | Tip-sample separation in metres |
+
+## Notes
+
+- **phase_to_force_gradient**: Convert MFM phase shift to force gradient using the cantilever spring constant relationship.
+- **force_gradient_to_field**: Recover the magnetic field from force gradient data via Fourier-domain deconvolution. Output unit: A/m.
+- **charge_density**: Compute effective magnetic charge density. Output unit: A/m².
+- **magnetisation**: Recover magnetisation from field data.
+- All operations use the lift height to set the correct spatial frequency transfer function.