Piezo response microscopy and d33 coefficient (AFM Dimension Icon)

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Ian Armstrong replied on Fri, May 22 2015 10:30 AM

Hi Lorenzo,

To measure the d33 coefficient from the PFM amplitude channel you need to perform the following calculation:

{the value you wish to use from the PFM amplitude channel [V] multiplied by the deflection sensitivity of the cantilever you are using [nm/V]} divided by {16 x the applied bias you are using [V]}

You can see by following the units this will leave you with nm/V

The number 16 is introduced as this  is a gain factor used in the instrument.

This calculation is in the manual or help file I believe under the "background contribution" section.

Best regards

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Lorenzo replied on Fri, May 22 2015 11:09 AM

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Dear Ian,

thank you for your explanation.

I saw in the manual the formula that you have cited, and this is a good start point.

but I have other questions...

1) the deflection sensitivity is a given value of each tip, or it should be calculated? Because I am using SCM-PIT probes, and I have just their deflection sensitivity value (eg 112 nm/V). Instead, in some studies that value was evaluated with a force-displacement curve.

2) Regarding "the value you wish to use from the PFM amplitude channel", it is represented by an average value obtained by a single scan, or it is referred to some particular points of a scan? In my case it is a delicate point, since I am studying nanocomposite, so I don't know if it is correct to calculate an average value of the total scanned area or not.

Thank you for your availability,

Lorenzo

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Ian Armstrong replied on Fri, May 22 2015 12:37 PM

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Hi Lorenzo,

1) the 112nm/V deflection sensitivity value is nominal, more accurate would be to evaluate it by doing a force curve and measuring the gradient in the contact portion of the curve.

2) this is your choice based on the sample - if your sample was completely homogeneous across the scanned area then you could use the average value of the entire scanned area. If you are interested in certain regions within the scan area then you will need to base the calculation on the amplitude in that particular region. You could gather this value by picking a point, looking at a cross section or small area and taking the average value.

Best regards

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Lorenzo replied on Mon, May 25 2015 2:31 AM

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Ok!

thank you Ian for your further explanations.

Best regards,

Lorenzo