Relationship between phase shift and energy dissipation in tapping-mode scanning force microscopy

Force curves taken during a load-unload cycle show the presence of a hysteresis loop. The area enclosed by the loop is used to measure the energy dissipated by the tip-sample interaction in tapping-mode scanning force microscopy. The values of the energy loss obtained from force curves are compared with the results derived from a model based on phase shift measurements. The agreement obtained between both methods demonstrates that for the same operating conditions, the higher the phase shift the larger the amount of energy dissipated by the tip-sample interaction. It also confirms the prediction that phase-contrast images can only arise if there are tip-sample inelastic interactions. (C) 1998 American Institute of Physics. [S0003-6951(98)03646-8].