DESIGN FOR A 10 PICOMETER MAGNETIC ACTUATOR

Scanning probe microscopies need actuators to produce controlled displ acements of surfaces in the nanoscale range. Usually piezoelectric cer amics are used for this function. In this article, we describe a magne tic way to produce a similar movement without the use of high voltage. The position is obtained with a precision lower than 10 pm in the ran ge of a hundred micrometers and a bandwidth of 1 kHz. All the paramete rs of this system can be accurately and easily determined. The knowled ge of an analytical form of the transient response of the actuator mak es the calibration of the position sensor needless. The direct measure ment of the position of the magnet gives entirely reliable results. Th is actuator could be, for example, applied to atomic force microscopy where a good precision in displacement is required to get force/distan ce curves or surface images. (C) 1997 American Institute of Physics.