Surface acoustic wave properties of fresnoite, Ba2Si2TiO8

Surface acoustic wave properties of fresnoite have been calculated from bulk material parameters and have been measured along several orientations on samples cut from Czochralski-grown crystals. Favorable properties are measured for the z-cut x-propagating wave: the coupling coefficient k2 is 0.016±0.003, the velocity is 2678 m/sec, and the temperature coefficient of delay is 51×10−6/ °C. These values, as well as those measured for the much lower coupling x-z and x-y surface waves, are in agreement with calculations. The calculations also predict that, for surface waves propagating in the x direction on a surface whose normal is at 45° to z and y axes, the coupling coefficient is 10% higher than calculated for the above z-x case.