Amplitude-frequency effects of Y-cut langanite and langatate

Amplitude-frequency effects of a y-cut langanite (LGN) resonator and a y-cut langatate (LGT) resonator were measured. The frequency shifts from the baseline frequency with 1 mA were measured as a function of drive currents up to 28 mA. While high drive current shifted the frequency, it also heated the crystal locally, causing temperature-related frequency changes. The local heat transfer and its influence on the frequency were analyzed. The amplitude-frequency shift was effectively measured, not affected by the temperature-related frequency changes. It is found that the 3/sup rd/, 5/sup th/, and 7/sup th/ overtones (OT's) behave as soft springs, i.e., resonant frequency decreases as drive current increases. The drive sensitivity coefficients of the 3/sup rd/ and 5/sup th/ OT's are in the vicinity of -2 ppm/(current density in [mA/mm/sup 2/])/sup 2/ or -2 ppb/(current in [mA])/sup 2/ for both resonators. The 7/sup th/ OT's are higher than the other OT's: -5/spl sim/-7 ppb/mA/sup 2/. The lowest drive sensitivity is -1.2 ppb/mA/sup 2/ on the 5/sup th/ OT of the LGT.