Elastic Properties of Oxides and the Search for Temperature-Compensated Materials
PENNSYLVANIA STATE UNIV UNIVERSITY PARK MATERIALS RESEARCH LAB
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New temperature-compensated high piezoelectric coupling crystals are needed for acoustic surface-wave matched filters, encoders, decoders, and related signal processing devices. Elastic coefficients, together with their pressure and temperature derivatives, are also important in materials science and in geophysics. Oxides show several correlations between structure type and elastic behavior. A simple mechanical analogy in which atomic bonds are simulated by springs connected in series and parallel is used to estimate the size and anisotropy of the elastic moduli. Magnitudes of the temperature and pressure derivatives of the stiffness coefficients are also predicted by the model. Crystallochemical factors conducive to anomalous elastic behavior are examined, with special attention to materials which become stiffer with increasing temperature.
- Solid State Physics