Effect of liquid on the magnetic force microscope imaging

It is known that when the probe vibrating in liquid, the oscillation of the cantilever is significantly damped by the interaction forces between the water molecule and the probe surface, which is known as the hydration force. Thus, the parameters of a tapping magnetic probe are affected. In this work, the resonant frequency, Q-factor and spring constant of the magnetic probe in air and liquid environments were analyzed. The MFM images of a hard disk acquired in ambient and liquid conditions were compared. It was found that the hydration force affected the parameters of the magnetic probe and then the quality of the MFM images was decreased. To improve the quality of the magnetic images, the drive amplitude and the lift height were adjusted. The results showed that the magnetic features were recognized with the increases of the drive amplitude and the appropriate lift height.