Acoustic loss in cultured quartz

摘要: The Q of a quartz resonator is limited by the design, mounting structure and electrodes, surrounding atmosphere, itself. loss all resonators interaction between active vibration thermal phonon bath. This intrinsic limits 5 MHz overtone AT-cut crystals to about 3 million. Defects cause additional losses. Of these, substitutional aluminum with its charge compensating-ion most important. Al-Li center which dominates in unswept cultured does not contribute any loss. However, Al-Na present grown without addition lithium mineralizer causes strong at 54 K crystals. Al-OH swept (and after irradiation) has peak near 600 K. Low-temperature peaks are associated Al-hole produced irradiation or vacuum electrolysis. BT-cut approximately one-fifth that an equivalent while SC-cuts intermediate. also observed low-frequency bar resonators. These results suggest defect couples modes. At high temperatures rapidly-increasing thermally-activated observed. temperature primarily due alkali ions have thermally escaped from Al-site. Other centers OH-growth defects do there alkali-compensated versions these just above room temperature. Sweeping converts into increases mechanical Q.