Out of plane piezoresponse force microscopy (PFM) on Lithium Niobate

Lithium Niobite (LiNbO3) is an optically transparent, piezo responsive material used, for example, in piezo sensors or in mobile phones. We tested a LiNbO3 sample (PFM03, obtained from TipsNano, Estonia) with CoreAFM. The sample has a regular domain structure with 10-µm period. The spontaneous polarization has the opposite direction in the neighboring domains.

To measure the piezoresponse during imaging, a 30kHz AC voltage with 5V amplitude was applied to the cantilever while raster scanning the tip over the sample. In response to the applied voltage, the sample periodically expands and shrinks, either in phase with or in counter phase to the excitation frequency. The periodic expansion is measured by the second internal lock-in amplifier of the CoreAFM controller and revealed a 180° phase shift between the domains.

Lithium Niobite (LiNbO3) is an optically transparent, piezo responsive material used, for example, in piezo sensors or in mobile phones. We tested a LiNbO3 sample (PFM03, obtained from TipsNano, Estonia) with CoreAFM. The sample has a regular domain structure with 10-µm period. The spontaneous polarization has the opposite direction in the neighboring domains.

To measure the piezoresponse during imaging, a 30kHz AC voltage with 5V amplitude was applied to the cantilever while raster scanning the tip over the sample. In response to the applied voltage, the sample periodically expands and shrinks, either in phase with or in counter phase to the excitation frequency. The periodic expansion is measured by the second internal lock-in amplifier of the CoreAFM controller and revealed a 180° phase shift between the domains.

Read more about PFM

PFM03 showing domains with different phase
3D representation of phase in color overlaid on topography of PFM03 showing domains with different phase.
Image size: 20 µm
Left-to-right profile of the phases signal
Left-to-right profile of the phases signal, showing the expected phase difference of 180° between between the domains of the PFM03 sample

Image processing was done with MountainsSPIP

Image courtesy: Brian Odermatt, EPFL, Lausanne

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