36 lines
2.2 KiB
Markdown
36 lines
2.2 KiB
Markdown
# PFM Analysis
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Compute polarization vectors from Piezoresponse Force Microscopy (PFM) data by combining vertical (VPFM) and lateral (LPFM) amplitude and phase channels into polarization magnitude, azimuth, and inclination maps. Equivalent to Gwyddion's `pfm.c` module.
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## Inputs
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| Name | Type | Required | Description |
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|------|------|----------|-------------|
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| vpfm_amplitude | DATA_FIELD | Yes | Vertical PFM amplitude channel |
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| lpfm_amplitude | DATA_FIELD | Yes | Lateral PFM amplitude channel |
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| vpfm_phase | DATA_FIELD | Yes | Vertical PFM phase channel (radians) |
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| lpfm_phase | DATA_FIELD | Yes | Lateral PFM phase channel (radians) |
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## Outputs
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| Name | Type | Description |
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|------|------|-------------|
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| magnitude | DATA_FIELD | Polarization vector magnitude |
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| azimuth | DATA_FIELD | In-plane polarization angle |
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| inclination | DATA_FIELD | Out-of-plane polarization angle (3D mode only) |
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## Controls
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| Name | Type | Default | Description |
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|------|------|---------|-------------|
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| mode | dropdown | 2d | Decomposition mode: 2d (in-plane only) or 3d (full polarization vector) |
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| lateral_sensitivity | FLOAT | 1.0 | Scale factor applied to the lateral signal to compensate for differing VPFM/LPFM detector sensitivities |
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## Notes
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- PFM measures the local piezoelectric response of ferroelectric materials by detecting surface deformation under an applied AC bias via the AFM cantilever.
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- In **2d** mode, only in-plane polarization is resolved from the LPFM channels; magnitude and azimuth are computed but inclination is not produced. In **3d** mode, both vertical and lateral channels are combined to reconstruct the full polarization vector, including inclination.
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- The **lateral_sensitivity** parameter compensates for the fact that vertical and lateral deflection detectors typically have different sensitivities. Set this to the ratio of LPFM to VPFM detector sensitivity for accurate vector reconstruction.
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- Phase inputs must be in radians. If your data is in degrees, convert before connecting (multiply by pi/180).
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- Amplitude channels should be unsigned (absolute) piezoresponse magnitudes; the phase channels encode the sign (direction) of the polarization.
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