Quartz Crystal ESR vs Temperature

Since it's more likely the crystal Q that's interesting, try searching on "crystal Q vs temp". You will find papers about that.

Cheers, Tom

The data sheets usually give a "series resistance" value. For a crystal, that's the same as "motional resistance" which are just the bulk losses in series resonance mode. These are a function of the crystal cut, geometry (round or square), purity, contact plating size, and mounting.

I vaguely recall (from 30 years ago) doing temperature runs of various crystals in a fixture. While we were primarily interested in their frequency versus temp characteristic, I also recorded the series resistance. The series resistance varied wildly over the production lots received from the vendors, but each crystal was fairly stable over temperature. I vaguely recall that it was almost linear, with a slight decrease in series resistance with increasing temperature.

Sorry, no references, publications, or models handy.

The normal quartz processing includes some water-cooled grinding and polishing; it turns out that OH radical contamination can dominate the internal losses. The effect, as I recall, is minimized at elevated temperature (80 C or so?). I dimly remember Hughes corporation was involved in making artificial quartz crystals, and found that growth in water caused the artificial quartz to be inferior to natural. Alas, this was 20 years ago, it'd take a search for 'alpha SiO2' in a good library to find a reference.

Which natural quartz? Quartz grows from igneous melts (granite) and hydrothermal action (the artificial process is similar).

Tim

-- Deep Fryer: A very philosophical monk. Website @

We didn't use water cooling or grinding and never got involved in the growing or slicing part. The blanks were supplied slightly low in frequency by the vendor. We used an SS White abrasive sand blaster to do the tuning. If too much was blasted off, elecroless silver was sprayed onto the contact plating to move it down in frequency. It was a manual process controlled by an operator manipulating a Morse code paddle. Tap to the left, and it sand blasts. Tap to the right, and it adding plating. It took considerable expertise and practice to get it right. The blank was anything but stable during this process and would frequently overshooting in both directions. The operator had to predict where the counter would eventually stop. The last tuning step was to blow off any residual crud from the surface with a compressed air blast. We tried various solvent baths and found that an air blast was good enough.