Magnetic force microscopy sensors providing in-plane and perpendicular sensitivity

We present a bimodal magnetic force microscopy sensor consisting of a conventional cantilever beam, a spacer element, and an iron-filled carbon nanotube. Depending on the mode of the cantilever's resonant flexural vibration, the sensor is sensitive to magnetic field derivatives parallel and perpendicular to the sample's surface. This multifunctionality is supported by the scalar-type behavior of the magnetic monopole-like end of the iron-filled carbon nanotube.