New Method for Measuring the Rotation Inertia of a Single 4He Crystal

A new method for measuring the nonclassical rotation inertia of a helium single crystal is presented. This takes advantage of large crystals grown under conditions minimizing stresses and structural defects. High quality and large mass of crystals allow significantly increasing inertia signals and therefore sensitivity of measurements and accuracy of results. A method is tested at temperatures from 0.6 to 1.7 K in a frequency range of 100–1000 Hz. It is also used for studying internal friction in a helium single crystal.