Field emission to control tip-sample distance in magnetic probe recording

An integrated method using field-emission to control the tip-sample distance for non-contact magnetic probe recording is presented, adopting the exponential relation between current and electric field as feedback. I/V characteristics that correspond well to field emission theory are measured using a probe coated with a 100 nm conductive diamond layer. By using feedback to control the tip-sample distance at constant current, the distance was increased by 2.8 nm per volt applied bias. The method was tested by scanning a probe coated with 20 nm chromium over a conducting nanopatterned sample, at bias voltages of 0.5V, 5.0V and 50.0V. The measurements confirm that field emission can be applied to control the tip-sample distance, with sufficient resolution and current stability for magnetic probe recording.