Method for measuring a piezoelectric response by means of a scanning probe microscope

A method for measuring a piezoelectric response of a sample by means of a scanning probe microscope, wherein said scanning probe microscope comprises a probe on a mechanical resonator, and an actuator for applying a mechanical force to said mechanical resonator,

• said method comprising the steps of:
• applying an AC-voltage UAC in order to generate an alternating electric field in said sample and thereby to generate the piezoelectric response of said sample, which piezoelectric response exerts a first oscillating force to said resonator through said probe;
• applying, by means of said actuator, a second oscillating force, in addition to said first oscillating force, to said resonator, wherein said second oscillating force has a frequency corresponding to a resonance frequency f of said resonator, thereby causing said resonator to perform a resonant oscillation;
• and
• deriving said piezoelectric response from an influence of said applied AC-voltage on said resonant oscillation,
• wherein said AC-voltage has a frequency equal to said resonance frequency f and a constant phase shift φ in respect to a motion of said resonator.