Contact resonance frequencies and their harmonics in scanning probe microscopy

Local characterizations of electric, magnetic, mechanical, electrochemical, and structural properties of materials by scanning probe microscopy (SPM) can be carried out by sensing variations of the contact cantilever's resonance frequencies, resulting in diverse microscopy techniques such as piezoresponse force microscopy (PFM), atomic force acoustic microscopy (AFAM) and piezomagnetic force microscopy (PmFM), to name a few. In this work, we provide a simple setup to determine such frequencies, together with the dynamic response of the SPM cantilever and its harmonics. The setup is less expensive when compared to the commercial versions and allows a better control of the in‐and‐out PFM. It is based on the use of the internal AC source of a lock‐in amplifier controlled by software developed in LabVIEW. In order to illustrate the utility of the contact resonance frequencies in the SPM, resonance‐PFM, PFM non‐linearities, discrimination of ferroelectric from non‐ferroelectric responses and PmFM measurements, and determination of the modulus of elasticity by AFAM are conducted.