Device and method in contacting atomic force microscopy with periodic modulation of the contact force for measuring the local elastic and anelastic properties of surfaces while keeping the deformation constant in the contact area of the measuring probe and sample surface

摘要

The method involves using a servo circuit to maintain a constant difference between the excitation amplitude and dynamic amplitude of a cantilever. The servo circuit may be a digital or analogue regulator (e.g. PID type). A DC voltage proportional to the dynamic deformation is generated using the amplitude channel for a lock-in amplifier or using an amplitude-to-DC converter. The regulator control parameter DC voltage is used for amplitude-modulating the excitation voltage for a displacer (e.g. piezoelectric actuator), such that the modulation amplitude is proportional to this output voltage.