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 molecular and the probe surface, which  is known as  the  hydration force. Thus, the 
parameters of a tapping magnetic probe  are  significantly 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  significantly affected  the parameters of the magnetic probe and then the quality of the MFM images was significantly 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