data type - deflection in contact mode???????

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stsolong replied on Tue, Jul 3 2012 5:27 AM

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Hi Sandeep,

´Deflection´ is a constant in contact mode. In the contact mode, the cantilever contacts the sample surface with a certain and constant force. The cantilever may goes up and down to follow the topography of the sample. But the contact force between the tip and the sample keeps constant.

Therefore, ´Deflection´ of cantilever is the presentation of the contact force. It is kind of an ´input´ parameter in order to get the height  image, not an ´output´ data.

Hope I could answer your question. If something is wrong, welcome the correction.

Solong

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Sandeep Singh replied on Tue, Jul 3 2012 9:54 AM

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hi solong

Thanku very much for the response.

yes you are absolutely right - contact mode maintains the constant deflection/force.

This thing came in my mind because -- what !!! if we talk about about constant height rather than constant force? If we talk about any characterization involving 2 pass technique e.g. EFM or MFM tip is lifted to a certain constant height and then tips behaviour is recorded in response to variation of electrical or magnetic force in 2nd pass. In this case if we are working in contact mode then tip will be lifted to user defined height then if we want to study the effect of magnetic / electric force, tip deflection will come into picture. so my question is in data type there is no option like "deflection" , in this case what could be the data type to be recorded?

I have earlier put a query regarding MFM using contact mode tips then i got a suggestion that we can give a try in contact mode by looking Deflection.........

looking for reply in this direction

Thanks & regards

Sandeep

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stsolong replied on Fri, Jul 6 2012 7:42 AM

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Hi Sandeep,

I see what you mean now. I haven´t tried either MFM nor EFM by myself. What I could answer is based on just theories.

For MFM, in the lift pass, the cantilever follows the stored surface topography and senses the change of phase or amplitude. Because the magnetic field will shift the resonance frequency of the cantilever. You may set a drive frequency for phase or amplitude detection. In this case, the recorded data type is ´amplitude´or ´phase´.

For EFM, it is almost the same. The electrostatic forces will change in cantilever resonant frequency. The output data could be phase or frequency. The ´amplitude´ is not recommended due to artifacts.

Regards,

Solong