Full-resonance Spectroscopy
Oscillated tip-sample interaction affects not only on amplitude and phase lag, but also on the resonant frequency f of cantilever vibration and on the shape of resonance curve (quality factor Q). Under scanning the changes of the both f and Q are observed. These changes are the results of various kind tip-sample interactions. For more complete characterization of these interactions it is useful to obtain resonant curves (RC) in each point of scan at certain tip-sample distance (full resonance spectroscopy (FRS): amplitude (f,x,y), where f is frequency). Then the acquired data can be treated and different parameters of interaction can be determined.
Changing of the tip-sample force derivatives under scanning leads to changing of the resonant frequency. Different dissipation processes cause changes of the resonance peak shape. As a result to characterise tip-sample interaction the maximal amplitude, resonance frequency and width at half maximum (WHM) or quality factor Q of cantilever oscillation can be determined in each point of scan. This technique can be applied to study for example magnetic dissipation processes
[1,2].
FRS allows detail analyzing of the tip-sample interaction without electronic modification. Maps of cantilever frequency, amplitude and quality factor changes can be obtained simultaneously for same area with this technique.
FRS helps to study any dissipation processes existing during scanning. If the sample consists of areas with different viscosity (e.g. polymer blend) then dissipation can be measured by force-modulation technique.
References
- J. Appl. Phys. 81(8), 1997, 5024.
- Appl. Phys. Lett. 74(3), 1999, 419-421.
