Electrostrictive actuator for scanned-probe microscope

Abstract

The electrostrictive actuator device of the present invention, which controls relative movement in a scanned-probe microscope between the tip of a probe and the surface of a sample, comprises two thin-walled cylindrical members formed of electrostrictive material. The first cylindrical member, which is connected to the microscope, has on each of its inner and outer surfaces a conductive layer that forms at least one electrode. Applying voltages to the electrodes on the inner and outer surfaces of the first cylindrical member controls the two-dimensional X-Y horizontal relative movement between the probe tip and the sample surface. The second cylindrical member of the actuator device is coaxially connected at one end with the first cylindrical member and at its opposite end with the sample or the probe. Both the inner and outer surfaces of the second member have conductive layers, each of which forms an electrode. Applying voltages to the electrodes on the inner and outer surfaces of the second cylindrical member controls the Z-direction vertical relative movement of the probe tip on or near the sample surface. In preferred embodiments of the actuator device of the invention, either or both of the conductive layers on the inner and outer surfaces of the first cylindrical member may comprise two opposite pairs of spaced apart electrodes. Also in accordance with the invention, a scanned-probe microscope apparatus comprises a microscope and the just-described electrostrictive actuator device comprising first and second cylindrical members for controlling, respectively, X-Y horizontal and Z-direction vertical movements.