The effect of temperature on the stability of mica standards of capacitance
G H Rayner, L.H. Ford · Journal of Scientific Instruments · 1964
Some types of standard mica capacitors of clamped construction show changes of capacitance which approximately obey an exponential law with a characteristic time constant of the order of 10 years. The paper shows that these secular changes are much hastened by raising the temperature 10 degc above the normal ambient, and that the ultimate secular stability is thereby improved. Appreciable transitory effects are caused by changes of temperature; experiments have shown that such changes must be kept both small and slow if the best stability is to be obtained.