The Growth Rate Dependence of the Internal Friction of Synthetic Quartz

The internal friction of 5 Mc/s shear waves in AT-cut synthetic quartz resonators has been measured over a temperature range of 4°-400 °K as a function of the rate of growth of the parent quartz crystal. It is found that the peak in the region of 25 °K decreases somewhat with increasing growth rate, whilst the 50 °K peak increases by two orders of magnitude for a fourfold increase in growth rate. Furthermore, the internal friction in the range 250°-400 °K rises exponentially in the faster grown material. Tentative explanations of these effects are given in terms of the current theories of the interaction of phonons and imperfections in dielectric crystals.