Two ``Whisker'' Straining Devices Suitable for Low Temperatures

Abstract

Two devices for straining ``whiskers'' are described. In the first device, the whisker is mounted on a Mylar film that is stretched by a differential screw. The entire device can be immersed in liquid helium, which eliminates thermal expansion problems in low temperature experiments. In the second device the whisker is mounted between two bimorphs of piezoelectric material. The piezoelectric puller is small enough to fit inside a 2.5 cm i.d. superconducting solenoid and still permit the entire device to be rotated about an axis perpendicular to the solenoid axis.