PFM Sample Preparation

The sample should be placed on an electrically conductive material, such as the sample chuck. It is not required to paste the sample with a conductive paste onto the chuck. However, to achieve stable mounting, Bruker recommends using conductive paste to fix the sample onto the sample chuck.

About the Piezoresponse Standard Sample

The standard Piezoresponse sample is a periodically poled lithium niobate (LiNbO₃) PPLN crystal. Lithium niobate is a ferroelectric material with coercive field of 2 x 10⁷ V/m. The piezoelectric coefficient d₃₃ = 7.5 pm/V and its surface polarization is 0.7 C/m². It is known from the literature T. Jungk, A. Hoffmann, and E. Soergel, “Quantitative analysis of ferroelectric domain imaging with piezoresponse force microscopy,” Applied Physics Letters, 89 163507 (2006).1 that lithium niobate exhibits only c-domains. The c-domains are oriented in the direction from the cantilever to the AFM tip and can be mapped using the vertical deflection signal. The a-domains are perpendicular to the direction from the cantilever to the AFM tip and can be mapped using the lateral deflection signal. The PPLN crystal is cut such that the c-axis (hence c-domains) is perpendicular to the crystal surface. This sample is mounted with a conductive paste onto a steel puck that may be placed on the sample chuck for the measurements.

Sample Setup for Operation Without Tip Bias

For certain applications or SPM systems (such as the Dimension FastScan), the user may choose to work without applying a bias to the probe tip.

1. Add a thin metal film on the sample surface.
2. Connect a wire between the sample surface and an AC function generator. The NanoScope V front panel can output an appropriate AC signal.

Open topic with navigation