M Habibnejad Korayem - College of Mech. Eng., Iran University of Science and Technology, Tehran, Iran
N Ebrahimi - College of Mech. Eng., Iran University of Science and Technology, Tehran, Iran,
M.M Eghbal - College of Mech. Eng., Iran University of Science and Technology, Tehran, Iran,

Attractive and repulsive force regimes of an atomic force microscope were investigated as a function of tipsample separation. In attraction regime, the net attractive force causes reduction of amplitude and in repulsion regime, the net repulsive force controls the dynamic of the cantilever. There is a strong jump in amplitude and phase diagrams that is always a result of coexistence of two states of oscillation. The nonlinear interaction force between the tip and sample surface is also modeled. A simulation environment is developed to analyze the dynamics of cantilever using the Bernoulli-Euler beam model.

Atomic force microscopy; DMT; Attractive and repulsive force regimes; Strong jumps