Reliable quadric for frequency-turnover temperature vs. orientation of rotated Y-cut quartz plate resonator oscillating in the third overtone C-mode in the vicinity of AT-cut

This paper describes the reliable quadric for third overtone frequency-turnover temperature vs. orientation of cut for rotated Y-cut quartz crystal plate in the vicinity of AT-cut in the temperature range -196~250°C. From the present relation we can show the useful piezoelectric cuts of quartz for the resonator and sensor at the elevated temperature region. In particular, the experiments are carried out in the vicinity of AT-cut