Identification of Materials using Direct Force Modulation Technique with Magnetic AFM Cantilever

With a direct force modulation technique we measured the regional stiffness of the self-assembled-(SAM) films. A magnetic thin film was deposited at the end of the backside of the AFM cantilever so as to apply forces directly to the tip through the external magnetic field of an electric coil. This technique is able to detect the difference between the phase-separated monolayer films with two similar stiffnesses composed of hydrocarbon and fluorocarbon and identify the components of the film. We obtained the effective spring constant of 4.8 N/m on hydrocarbon SAM and 6.5 N/m on fluorocarbon SAM at the applied force of 1 nN.