Tip-sample Distance Control for Magnetic Probe Recording

In this work we present a method for tip-sample distance control in probe microscopy and probe recording by using field emission current detection as a feedback signal. Field emission currents flow when a large enough electric field is applied between the probe tip and the recording medium. The current varies exponentially with the applied electric field, which in turn is more or less proportional to the tip-sample distance [1]. High lateral and vertical resolutions are possible, perpendicular to the surface in sub-nm range and in the surface plane on the order of the field emitter radius [2]. Next to controlling the tip-sample distance, the cantilever resonance can in principle also be obtained. Since changes in resonance frequency are proportional to changes in the magnetic stray field derivates, this method can result in an integrated method for data detection for probe recording or Magnetic Force Microscopy (MFM).